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<h1 id="firstHeading" class="firstHeading"><span style="font-size:0.7em; line-height:130%">Standard library header</span> &lt;ranges&gt; <span class="t-mark-rev t-since-cxx20">(C++20)</span></h1>
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</table></div></td></tr>
<tr class="t-nv-h2"><td colspan="5"> Containers</td></tr>
<tr class="t-nv-col-table"><td><div><table class="t-nv-begin" cellpadding="0" style="">
<tr class="t-nv"><td colspan="5"> <a href="span.html" title="cpp/header/span"><tt>&lt;span&gt;</tt></a> <span class="t-mark-rev t-since-cxx20">(C++20)</span></td></tr>
<tr class="t-nv"><td colspan="5"> <a href="array.html" title="cpp/header/array"><tt>&lt;array&gt;</tt></a> <span class="t-mark-rev t-since-cxx11">(C++11)</span></td></tr>
<tr class="t-nv"><td colspan="5"> <a href="vector.html" title="cpp/header/vector"><tt>&lt;vector&gt;</tt></a></td></tr>
</table></div></td><td><div><table class="t-nv-begin" cellpadding="0" style="">
<tr class="t-nv"><td colspan="5"> <a href="deque.html" title="cpp/header/deque"><tt>&lt;deque&gt;</tt></a></td></tr>
<tr class="t-nv"><td colspan="5"> <a href="forward_list.html" title="cpp/header/forward list"><tt>&lt;forward_list&gt;</tt></a> <span class="t-mark-rev t-since-cxx11">(C++11)</span></td></tr>
<tr class="t-nv"><td colspan="5"> <a href="list.html" title="cpp/header/list"><tt>&lt;list&gt;</tt></a></td></tr>
</table></div></td><td><div><table class="t-nv-begin" cellpadding="0" style="">
<tr class="t-nv"><td colspan="5"> <a href="map.html" title="cpp/header/map"><tt>&lt;map&gt;</tt></a></td></tr>
<tr class="t-nv"><td colspan="5"> <a href="set.html" title="cpp/header/set"><tt>&lt;set&gt;</tt></a></td></tr>
<tr class="t-nv"><td colspan="5"> <a href="queue.html" title="cpp/header/queue"><tt>&lt;queue&gt;</tt></a></td></tr>
</table></div></td><td><div><table class="t-nv-begin" cellpadding="0" style="">
<tr class="t-nv"><td colspan="5"> <a href="unordered_map.html" title="cpp/header/unordered map"><tt>&lt;unordered_map&gt;</tt></a> <span class="t-mark-rev t-since-cxx11">(C++11)</span></td></tr>
<tr class="t-nv"><td colspan="5"> <a href="unordered_set.html" title="cpp/header/unordered set"><tt>&lt;unordered_set&gt;</tt></a> <span class="t-mark-rev t-since-cxx11">(C++11)</span></td></tr>
<tr class="t-nv"><td colspan="5"> <a href="stack.html" title="cpp/header/stack"><tt>&lt;stack&gt;</tt></a></td></tr>
</table></div></td></tr>
<tr class="t-nv-h2"><td colspan="5"> Iterators</td></tr>
<tr class="t-nv"><td colspan="5"> <a href="iterator.html" title="cpp/header/iterator"><tt>&lt;iterator&gt;</tt></a></td></tr>
<tr class="t-nv-h2"><td colspan="5"> Ranges</td></tr>
<tr class="t-nv"><td colspan="5"> <strong class="selflink"><tt>&lt;ranges&gt;</tt></strong> <span class="t-mark-rev t-since-cxx20">(C++20)</span></td></tr>
<tr class="t-nv-h2"><td colspan="5"> Algorithms</td></tr>
<tr class="t-nv-col-table"><td><div><table class="t-nv-begin" cellpadding="0" style="">
<tr class="t-nv"><td colspan="5"> <a href="algorithm.html" title="cpp/header/algorithm"><tt>&lt;algorithm&gt;</tt></a></td></tr>
</table></div></td><td><div><table class="t-nv-begin" cellpadding="0" style="">
<tr class="t-nv"><td colspan="5"> <a href="execution.html" title="cpp/header/execution"><tt>&lt;execution&gt;</tt></a> <span class="t-mark-rev t-since-cxx17">(C++17)</span></td></tr>
</table></div></td></tr>
<tr class="t-nv-h2"><td colspan="5"> Numerics</td></tr>
<tr class="t-nv-col-table"><td><div><table class="t-nv-begin" cellpadding="0" style="">
<tr class="t-nv"><td colspan="5"> <a href="complex.html" title="cpp/header/complex"><tt>&lt;complex&gt;</tt></a></td></tr>
<tr class="t-nv"><td colspan="5"> <a href="random.html" title="cpp/header/random"><tt>&lt;random&gt;</tt></a> <span class="t-mark-rev t-since-cxx11">(C++11)</span></td></tr>
</table></div></td><td><div><table class="t-nv-begin" cellpadding="0" style="">
<tr class="t-nv"><td colspan="5"> <a href="valarray.html" title="cpp/header/valarray"><tt>&lt;valarray&gt;</tt></a></td></tr>
<tr class="t-nv"><td colspan="5"> <a href="numeric.html" title="cpp/header/numeric"><tt>&lt;numeric&gt;</tt></a></td></tr>
</table></div></td><td><div><table class="t-nv-begin" cellpadding="0" style="">
<tr class="t-nv"><td colspan="5"> <a href="bit.html" title="cpp/header/bit"><tt>&lt;bit&gt;</tt></a> <span class="t-mark-rev t-since-cxx20">(C++20)</span></td></tr>
<tr class="t-nv"><td colspan="5"> <a href="numbers.html" title="cpp/header/numbers"><tt>&lt;numbers&gt;</tt></a> <span class="t-mark-rev t-since-cxx20">(C++20)</span></td></tr>
</table></div></td><td><div><table class="t-nv-begin" cellpadding="0" style="">
<tr class="t-nv"><td colspan="5"> <a href="cfenv.html" title="cpp/header/cfenv"><tt>&lt;cfenv&gt;</tt></a> <span class="t-mark-rev t-since-cxx11">(C++11)</span></td></tr>
<tr class="t-nv"><td colspan="5"> <a href="cmath.html" title="cpp/header/cmath"><tt>&lt;cmath&gt;</tt></a></td></tr>
</table></div></td></tr>
<tr class="t-nv-h2"><td colspan="5"> Input/Output</td></tr>
<tr class="t-nv-col-table"><td><div><table class="t-nv-begin" cellpadding="0" style="">
<tr class="t-nv"><td colspan="5"> <a href="iosfwd.html" title="cpp/header/iosfwd"><tt>&lt;iosfwd&gt;</tt></a></td></tr>
<tr class="t-nv"><td colspan="5"> <a href="ios.html" title="cpp/header/ios"><tt>&lt;ios&gt;</tt></a></td></tr>
<tr class="t-nv"><td colspan="5"> <a href="iomanip.html" title="cpp/header/iomanip"><tt>&lt;iomanip&gt;</tt></a></td></tr>
<tr class="t-nv"><td colspan="5"> <a href="streambuf.html" title="cpp/header/streambuf"><tt>&lt;streambuf&gt;</tt></a></td></tr>
</table></div></td><td><div><table class="t-nv-begin" cellpadding="0" style="">
<tr class="t-nv"><td colspan="5"> <a href="istream.html" title="cpp/header/istream"><tt>&lt;istream&gt;</tt></a></td></tr>
<tr class="t-nv"><td colspan="5"> <a href="ostream.html" title="cpp/header/ostream"><tt>&lt;ostream&gt;</tt></a></td></tr>
<tr class="t-nv"><td colspan="5"> <a href="iostream.html" title="cpp/header/iostream"><tt>&lt;iostream&gt;</tt></a></td></tr>
<tr class="t-nv"><td colspan="5"> <br>
</td></tr>
</table></div></td><td><div><table class="t-nv-begin" cellpadding="0" style="">
<tr class="t-nv"><td colspan="5"> <a href="syncstream.html" title="cpp/header/syncstream"><tt>&lt;syncstream&gt;</tt></a> <span class="t-mark-rev t-since-cxx20">(C++20)</span></td></tr>
<tr class="t-nv"><td colspan="5"> <a href="spanstream.html" title="cpp/header/spanstream"><tt>&lt;spanstream&gt;</tt></a> <span class="t-mark-rev t-since-cxx23">(C++23)</span></td></tr>
<tr class="t-nv"><td colspan="5"> <a href="sstream.html" title="cpp/header/sstream"><tt>&lt;sstream&gt;</tt></a></td></tr>
<tr class="t-nv"><td colspan="5"> <a href="fstream.html" title="cpp/header/fstream"><tt>&lt;fstream&gt;</tt></a></td></tr>
</table></div></td><td><div><table class="t-nv-begin" cellpadding="0" style="">
<tr class="t-nv"><td colspan="5"> <a href="cstdio.html" title="cpp/header/cstdio"><tt>&lt;cstdio&gt;</tt></a></td></tr>
<tr class="t-nv"><td colspan="5"> <a href="cinttypes.html" title="cpp/header/cinttypes"><tt>&lt;cinttypes&gt;</tt></a> <span class="t-mark-rev t-since-cxx11">(C++11)</span></td></tr>
<tr class="t-nv"><td colspan="5"> <a href="strstream.html" title="cpp/header/strstream"><tt>&lt;strstream&gt;</tt></a> <span class="t-mark">(C++98/)</span></td></tr>
<tr class="t-nv"><td colspan="5"> <br>
</td></tr>
</table></div></td></tr>
<tr class="t-nv-h2"><td colspan="5"> Regular expressions</td></tr>
<tr class="t-nv"><td colspan="5"> <a href="regex.html" title="cpp/header/regex"><tt>&lt;regex&gt;</tt></a> <span class="t-mark-rev t-since-cxx11">(C++11)</span></td></tr>
<tr class="t-nv-h2"><td colspan="5"> Filesystem support</td></tr>
<tr class="t-nv"><td colspan="5"> <a href="filesystem.html" title="cpp/header/filesystem"><tt>&lt;filesystem&gt;</tt></a> <span class="t-mark-rev t-since-cxx17">(C++17)</span></td></tr>
<tr class="t-nv-h2"><td colspan="5"> Thread support</td></tr>
<tr class="t-nv-col-table"><td><div><table class="t-nv-begin" cellpadding="0" style="">
<tr class="t-nv"><td colspan="5"> <a href="thread.html" title="cpp/header/thread"><tt>&lt;thread&gt;</tt></a> <span class="t-mark-rev t-since-cxx11">(C++11)</span></td></tr>
<tr class="t-nv"><td colspan="5"> <a href="atomic.html" title="cpp/header/atomic"><tt>&lt;atomic&gt;</tt></a> <span class="t-mark-rev t-since-cxx11">(C++11)</span></td></tr>
<tr class="t-nv"><td colspan="5"> <a href="mutex.html" title="cpp/header/mutex"><tt>&lt;mutex&gt;</tt></a> <span class="t-mark-rev t-since-cxx11">(C++11)</span></td></tr>
</table></div></td><td><div><table class="t-nv-begin" cellpadding="0" style="">
<tr class="t-nv"><td colspan="5"> <a href="shared_mutex.html" title="cpp/header/shared mutex"><tt>&lt;shared_mutex&gt;</tt></a> <span class="t-mark-rev t-since-cxx14">(C++14)</span></td></tr>
<tr class="t-nv"><td colspan="5"> <a href="condition_variable.html" title="cpp/header/condition variable"><tt>&lt;condition_variable&gt;</tt></a> <span class="t-mark-rev t-since-cxx11">(C++11)</span>  </td></tr>
<tr class="t-nv"><td colspan="5"> <a href="future.html" title="cpp/header/future"><tt>&lt;future&gt;</tt></a> <span class="t-mark-rev t-since-cxx11">(C++11)</span></td></tr>
</table></div></td><td><div><table class="t-nv-begin" cellpadding="0" style="">
<tr class="t-nv"><td colspan="5"> <a href="stop_token.html" title="cpp/header/stop token"><tt>&lt;stop_token&gt;</tt></a> <span class="t-mark-rev t-since-cxx20">(C++20)</span></td></tr>
<tr class="t-nv"><td colspan="5"> <a href="semaphore.html" title="cpp/header/semaphore"><tt>&lt;semaphore&gt;</tt></a> <span class="t-mark-rev t-since-cxx20">(C++20)</span></td></tr>
<tr class="t-nv"><td colspan="5"> <br>
</td></tr>
</table></div></td><td><div><table class="t-nv-begin" cellpadding="0" style="">
<tr class="t-nv"><td colspan="5"> <a href="latch.html" title="cpp/header/latch"><tt>&lt;latch&gt;</tt></a> <span class="t-mark-rev t-since-cxx20">(C++20)</span></td></tr>
<tr class="t-nv"><td colspan="5"> <a href="barrier.html" title="cpp/header/barrier"><tt>&lt;barrier&gt;</tt></a> <span class="t-mark-rev t-since-cxx20">(C++20)</span></td></tr>
<tr class="t-nv"><td colspan="5"> <br>
</td></tr>
</table></div></td></tr>
<tr class="t-nv-h2"><td colspan="5"> C compatibility</td></tr>
<tr class="t-nv-col-table"><td><div><table class="t-nv-begin" cellpadding="0" style="">
<tr class="t-nv"><td colspan="5"> <a href="cstdbool.html" title="cpp/header/cstdbool"><tt>&lt;cstdbool&gt;</tt></a> <span class="t-mark">(C++11/17/20)</span></td></tr>
<tr class="t-nv"><td colspan="5"> <a href="ccomplex.html" title="cpp/header/ccomplex"><tt>&lt;ccomplex&gt;</tt></a> <span class="t-mark">(C++11/17/20)</span></td></tr>
</table></div></td><td><div><table class="t-nv-begin" cellpadding="0" style="">
<tr class="t-nv"><td colspan="5"> <a href="ctgmath.html" title="cpp/header/ctgmath"><tt>&lt;ctgmath&gt;</tt></a> <span class="t-mark">(C++11/17/20)</span></td></tr>
<tr class="t-nv"><td colspan="5"> <a href="cstdalign.html" title="cpp/header/cstdalign"><tt>&lt;cstdalign&gt;</tt></a> <span class="t-mark">(C++11/17/20)</span></td></tr>
</table></div></td><td><div><table class="t-nv-begin" cellpadding="0" style="">
<tr class="t-nv"><td colspan="5"> <a href="ciso646.html" title="cpp/header/ciso646"><tt>&lt;ciso646&gt;</tt></a> <span class="t-mark-rev t-until-cxx20">(until C++20)</span></td></tr>
<tr class="t-nv"><td colspan="5"> <a href="stdatomic.h.html" title="cpp/header/stdatomic.h"><tt>&lt;stdatomic.h&gt;</tt></a></td></tr>
</table></div></td></tr>
</table></div><div></div></div></div></div><div class="t-navbar-sep"> </div></div>
<p>This header is part of the <a href="../ranges.html" title="cpp/ranges">ranges</a> library.
</p>
<h3><span class="mw-headline" id="Namespace_aliases"> Namespace aliases </span></h3>
<table class="t-dcl-begin"><tbody>

<tr class="t-dcl">
<td class="t-dcl-nopad"> <div><span class="mw-geshi cpp source-cpp"><span class="kw1">namespace</span> std <span class="br0">{</span><br>
<p>    <span class="kw1">namespace</span> views <span class="sy1">=</span> ranges<span class="sy4">::</span><span class="me2">views</span><span class="sy4">;</span><br>
</p>
<span class="br0">}</span></span></div></td>
<td class="t-dcl-nopad">  </td>
<td class="t-dcl-nopad">  </td>
</tr>
<tr class="t-dcl-sep"><td></td><td></td><td></td></tr>
</tbody></table>
<p>The namespace alias <code>std::views</code> is provided as a shorthand for <code>std::ranges::views</code>.
</p>
<table class="t-dsc-begin">

<tr>
<td colspan="2"> <h3> <span class="mw-headline" id="Concepts"> Concepts</span></h3>
</td></tr>

<tr>
<td colspan="2"> <h5> <span class="mw-headline" id="Range_concepts">  Range concepts </span></h5>
</td></tr>

<tr class="t-dsc-header">
<td colspan="2"> <div>Defined in  namespace <code>std::ranges</code> </div>
</td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../ranges/range.html" title="cpp/ranges/range"> <span class="t-lines"><span>ranges::range</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div></div>
</td>
<td>   specifies that a type is a range, that is, it provides a <code>begin</code> iterator and an <code>end</code> sentinel  <br> <span class="t-mark">(concept)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../ranges/borrowed_range.html" title="cpp/ranges/borrowed range"> <span class="t-lines"><span>ranges::borrowed_range</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div></div>
</td>
<td>   specifies that a type is a <a href="../ranges/range.html" title="cpp/ranges/range"><code>range</code></a> and iterators obtained from an expression of it can be safely returned without danger of dangling  <br> <span class="t-mark">(concept)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../ranges/sized_range.html" title="cpp/ranges/sized range"> <span class="t-lines"><span>ranges::sized_range</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div></div>
</td>
<td>   specifies that a range knows its size in constant time <br> <span class="t-mark">(concept)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../ranges/view.html" title="cpp/ranges/view"> <span class="t-lines"><span>ranges::view</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div></div>
</td>
<td>  specifies that a range is a view, that is, it has constant time copy/move/assignment <br> <span class="t-mark">(concept)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../ranges/input_range.html" title="cpp/ranges/input range"> <span class="t-lines"><span>ranges::input_range</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div></div>
</td>
<td>  specifies a range whose iterator type satisfies <a href="../iterator/input_iterator.html" title="cpp/iterator/input iterator"><code>input_iterator</code></a>  <br> <span class="t-mark">(concept)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../ranges/output_range.html" title="cpp/ranges/output range"> <span class="t-lines"><span>ranges::output_range</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div></div>
</td>
<td>  specifies a range whose iterator type satisfies <a href="../iterator/output_iterator.html" title="cpp/iterator/output iterator"><code>output_iterator</code></a> <br> <span class="t-mark">(concept)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../ranges/forward_range.html" title="cpp/ranges/forward range"> <span class="t-lines"><span>ranges::forward_range</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div></div>
</td>
<td>  specifies a range whose iterator type satisfies <a href="../iterator/forward_iterator.html" title="cpp/iterator/forward iterator"><code>forward_iterator</code></a> <br> <span class="t-mark">(concept)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../ranges/bidirectional_range.html" title="cpp/ranges/bidirectional range"> <span class="t-lines"><span>ranges::bidirectional_range</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div></div>
</td>
<td>  specifies a range whose iterator type satisfies <a href="../iterator/bidirectional_iterator.html" title="cpp/iterator/bidirectional iterator"><code>bidirectional_iterator</code></a> <br> <span class="t-mark">(concept)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../ranges/random_access_range.html" title="cpp/ranges/random access range"> <span class="t-lines"><span>ranges::random_access_range</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div></div>
</td>
<td>  specifies a range whose iterator type satisfies <a href="../iterator/random_access_iterator.html" title="cpp/iterator/random access iterator"><code>random_access_iterator</code></a> <br> <span class="t-mark">(concept)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../ranges/contiguous_range.html" title="cpp/ranges/contiguous range"> <span class="t-lines"><span>ranges::contiguous_range</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div></div>
</td>
<td>  specifies a range whose iterator type satisfies <a href="../iterator/contiguous_iterator.html" title="cpp/iterator/contiguous iterator"><code>contiguous_iterator</code></a> <br> <span class="t-mark">(concept)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../ranges/common_range.html" title="cpp/ranges/common range"> <span class="t-lines"><span>ranges::common_range</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div></div>
</td>
<td>   specifies that a range has identical iterator and sentinel types  <br> <span class="t-mark">(concept)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../ranges/viewable_range.html" title="cpp/ranges/viewable range"> <span class="t-lines"><span>ranges::viewable_range</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div></div>
</td>
<td>   specifies the requirements for a <a href="../ranges/range.html" title="cpp/ranges/range"><code>range</code></a> to be safely convertible to a <a href="../ranges/view.html" title="cpp/ranges/view"><code>view</code></a>  <br> <span class="t-mark">(concept)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../ranges/constant_range.html" title="cpp/ranges/constant range"> <span class="t-lines"><span>ranges::constant_range</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx23">(C++23)</span></span></span></div></div>
</td>
<td>  specifies that a range has read-only elements <br> <span class="t-mark">(concept)</span> </td></tr>


<tr>
<td colspan="2"> <h3> <span class="mw-headline" id="Functions"> Functions</span></h3>
</td></tr>

<tr>
<td colspan="2"> <h5> <span class="mw-headline" id="Range_conversions">  Range conversions </span></h5>
</td></tr>

<tr class="t-dsc-header">
<td colspan="2"> <div>Defined in  namespace <code>std::ranges</code> </div>
</td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../ranges/to.html" title="cpp/ranges/to"> <span class="t-lines"><span>ranges::to</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx23">(C++23)</span></span></span></div></div>
</td>
<td>   constructs a non-view range from another range  <br> <span class="t-mark">(function template)</span> </td></tr>


<tr>
<td colspan="2"> <h3> <span class="mw-headline" id="Classes"> Classes</span></h3>
</td></tr>

<tr>
<td colspan="2"> <h5> <span class="mw-headline" id="Range_primitives">  Range primitives </span></h5>
</td></tr>

<tr class="t-dsc-header">
<td colspan="2"> <div>Defined in  namespace <code>std::ranges</code> </div>
</td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../ranges/iterator_t.html" title="cpp/ranges/iterator t"> <span class="t-lines"><span>ranges::iterator_t</span><span>ranges::const_iterator_t</span><span>ranges::sentinel_t</span><span>ranges::range_difference_t</span><span>ranges::range_size_t </span><span>ranges::range_value_t</span><span>ranges::range_reference_t</span><span>ranges::range_const_reference_t</span><span>ranges::range_rvalue_reference_t</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span><span><span class="t-mark-rev t-since-cxx23">(C++23)</span></span><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span><span><span class="t-mark-rev t-since-cxx23">(C++23)</span></span><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div></div>
</td>
<td>  obtains associated types of a range <br> <span class="t-mark">(alias template)</span> </td></tr>

<tr>
<td colspan="2"> <h5> <span class="mw-headline" id="Views">  Views </span></h5>
</td></tr>

<tr class="t-dsc-header">
<td colspan="2"> <div>Defined in  namespace <code>std::ranges</code> </div>
</td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../ranges/view_interface.html" title="cpp/ranges/view interface"> <span class="t-lines"><span>ranges::view_interface</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div></div>
</td>
<td>   helper class template for defining a <a href="../ranges/view.html" title="cpp/ranges/view"><code>view</code></a>, using the <a href="../language/crtp.html" title="cpp/language/crtp">curiously recurring template pattern</a>  <br> <span class="t-mark">(class template)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../ranges/subrange.html" title="cpp/ranges/subrange"> <span class="t-lines"><span>ranges::subrange</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div></div>
</td>
<td>   combines an iterator-sentinel pair into a <a href="../ranges/view.html" title="cpp/ranges/view"><code>view</code></a>  <br> <span class="t-mark">(class template)</span> </td></tr>

<tr>
<td colspan="2"> <h5> <span class="mw-headline" id="Dangling_iterator_handling">  Dangling iterator handling </span></h5>
</td></tr>

<tr class="t-dsc-header">
<td colspan="2"> <div>Defined in  namespace <code>std::ranges</code> </div>
</td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../ranges/dangling.html" title="cpp/ranges/dangling"> <span class="t-lines"><span>ranges::dangling</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div></div>
</td>
<td>   a placeholder type indicating that an iterator or a <code>subrange</code> should not be returned since it would be dangling  <br> <span class="t-mark">(class)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../ranges/borrowed_iterator_t.html" title="cpp/ranges/borrowed iterator t"> <span class="t-lines"><span>ranges::borrowed_iterator_t</span><span>ranges::borrowed_subrange_t</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div></div>
</td>
<td>   obtains iterator type or <code>subrange</code> type of a <a href="../ranges/borrowed_range.html" title="cpp/ranges/borrowed range"><code>borrowed_range</code></a>  <br> <span class="t-mark">(alias template)</span> </td></tr>

<tr>
<td colspan="2"> <h5> <span class="mw-headline" id="Range_adaptor_objects_utility">  Range adaptor objects utility </span></h5>
</td></tr>

<tr class="t-dsc-header">
<td colspan="2"> <div>Defined in  namespace <code>std::ranges</code> </div>
</td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="https://en.cppreference.com/mwiki/index.php?title=cpp/ranges/range_adaptor_closure&amp;action=edit&amp;redlink=1" class="new" title="cpp/ranges/range adaptor closure (page does not exist)"> <span class="t-lines"><span>ranges::range_adaptor_closure</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx23">(C++23)</span></span></span></div></div>
</td>
<td>   helper base class template for defining a range adaptor closure object  <br> <span class="t-mark">(class template)</span> </td></tr>

<tr>
<td colspan="2"> <h5> <span class="mw-headline" id="Factories">  Factories </span></h5>
</td></tr>

<tr class="t-dsc-header">
<td colspan="2"> <div>Defined in  namespace <code>std::ranges</code> </div>
</td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../ranges/empty_view.html" title="cpp/ranges/empty view"> <span class="t-lines"><span>ranges::empty_view</span><span>views::empty</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div></div>
</td>
<td>   an empty <a href="../ranges/view.html" title="cpp/ranges/view"><code>view</code></a> with no elements  <br> <span class="t-mark">(class template)</span> <span class="t-mark">(variable template)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../ranges/single_view.html" title="cpp/ranges/single view"> <span class="t-lines"><span>ranges::single_view</span><span>views::single</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div></div>
</td>
<td>   a <a href="../ranges/view.html" title="cpp/ranges/view"><code>view</code></a> that contains a single element of a specified value  <br> <span class="t-mark">(class template)</span> <span class="t-mark">(customization point object)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../ranges/iota_view.html" title="cpp/ranges/iota view"> <span class="t-lines"><span>ranges::iota_view</span><span>views::iota</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div></div>
</td>
<td>   a <a href="../ranges/view.html" title="cpp/ranges/view"><code>view</code></a> consisting of a sequence generated by repeatedly incrementing an initial value  <br> <span class="t-mark">(class template)</span> <span class="t-mark">(customization point object)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../ranges/basic_istream_view.html" title="cpp/ranges/basic istream view"> <span class="t-lines"><span>ranges::basic_istream_view</span><span>views::istream</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div></div>
</td>
<td>   a <a href="../ranges/view.html" title="cpp/ranges/view"><code>view</code></a> consisting of the elements obtained by successive application of operator&gt;&gt; on the associated input stream <br> <span class="t-mark">(class template)</span> <span class="t-mark">(customization point object)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="https://en.cppreference.com/mwiki/index.php?title=cpp/ranges/repeat_view&amp;action=edit&amp;redlink=1" class="new" title="cpp/ranges/repeat view (page does not exist)"> <span class="t-lines"><span>ranges::repeat_view</span><span>views::repeat</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx23">(C++23)</span></span></span></div></div>
</td>
<td>   a <a href="../ranges/view.html" title="cpp/ranges/view"><code>view</code></a> consisting of a generated sequence by repeatedly producing the same value  <br> <span class="t-mark">(class template)</span> <span class="t-mark">(customization point object)</span> </td></tr>

<tr>
<td colspan="2"> <h5> <span class="mw-headline" id="Adaptors">  Adaptors </span></h5>
</td></tr>

<tr class="t-dsc-header">
<td colspan="2"> <div>Defined in  namespace <code>std::ranges</code> </div>
</td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../ranges/all_view.html" title="cpp/ranges/all view"> <span class="t-lines"><span>views::all_t</span><span>views::all</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div></div>
</td>
<td>  a <a href="../ranges/view.html" title="cpp/ranges/view"><code>view</code></a> that includes all elements of a <a href="../ranges/range.html" title="cpp/ranges/range"><code>range</code></a> <br> <span class="t-mark">(alias template)</span> <span class="t-mark">(range adaptor object)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../ranges/ref_view.html" title="cpp/ranges/ref view"> <span class="t-lines"><span>ranges::ref_view</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div></div>
</td>
<td>   a <a href="../ranges/view.html" title="cpp/ranges/view"><code>view</code></a> of the elements of some other <a href="../ranges/range.html" title="cpp/ranges/range"><code>range</code></a> <br> <span class="t-mark">(class template)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../ranges/owning_view.html" title="cpp/ranges/owning view"> <span class="t-lines"><span>ranges::owning_view</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div></div>
</td>
<td>   a <a href="../ranges/view.html" title="cpp/ranges/view"><code>view</code></a> with unique ownership of some <a href="../ranges/range.html" title="cpp/ranges/range"><code>range</code></a> <br> <span class="t-mark">(class template)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../ranges/filter_view.html" title="cpp/ranges/filter view"> <span class="t-lines"><span>ranges::filter_view</span><span>views::filter</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div></div>
</td>
<td>   a <a href="../ranges/view.html" title="cpp/ranges/view"><code>view</code></a> that consists of the elements of a <a href="../ranges/range.html" title="cpp/ranges/range"><code>range</code></a> that satisfies a predicate  <br> <span class="t-mark">(class template)</span> <span class="t-mark">(range adaptor object)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../ranges/transform_view.html" title="cpp/ranges/transform view"> <span class="t-lines"><span>ranges::transform_view</span><span>views::transform</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div></div>
</td>
<td>   a <a href="../ranges/view.html" title="cpp/ranges/view"><code>view</code></a> of a sequence that applies a transformation function to each element  <br> <span class="t-mark">(class template)</span> <span class="t-mark">(range adaptor object)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../ranges/take_view.html" title="cpp/ranges/take view"> <span class="t-lines"><span>ranges::take_view</span><span>views::take</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div></div>
</td>
<td>   a <a href="../ranges/view.html" title="cpp/ranges/view"><code>view</code></a> consisting of the first N elements of another <a href="../ranges/view.html" title="cpp/ranges/view"><code>view</code></a>  <br> <span class="t-mark">(class template)</span> <span class="t-mark">(range adaptor object)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../ranges/take_while_view.html" title="cpp/ranges/take while view"> <span class="t-lines"><span>ranges::take_while_view</span><span>views::take_while</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div></div>
</td>
<td>   a <a href="../ranges/view.html" title="cpp/ranges/view"><code>view</code></a> consisting of the initial elements of another <a href="../ranges/view.html" title="cpp/ranges/view"><code>view</code></a>, until the first element on which a predicate returns false <br> <span class="t-mark">(class template)</span> <span class="t-mark">(range adaptor object)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../ranges/drop_view.html" title="cpp/ranges/drop view"> <span class="t-lines"><span>ranges::drop_view</span><span>views::drop</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div></div>
</td>
<td>   a <a href="../ranges/view.html" title="cpp/ranges/view"><code>view</code></a> consisting of elements of another <a href="../ranges/view.html" title="cpp/ranges/view"><code>view</code></a>, skipping the first N elements <br> <span class="t-mark">(class template)</span> <span class="t-mark">(range adaptor object)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../ranges/drop_while_view.html" title="cpp/ranges/drop while view"> <span class="t-lines"><span>ranges::drop_while_view</span><span>views::drop_while</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div></div>
</td>
<td>   a <a href="../ranges/view.html" title="cpp/ranges/view"><code>view</code></a> consisting of the elements of another <a href="../ranges/view.html" title="cpp/ranges/view"><code>view</code></a>, skipping the initial subsequence of elements until the first element where the predicate returns false <br> <span class="t-mark">(class template)</span> <span class="t-mark">(range adaptor object)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../ranges/join_view.html" title="cpp/ranges/join view"> <span class="t-lines"><span>ranges::join_view</span><span>views::join</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div></div>
</td>
<td>   a <a href="../ranges/view.html" title="cpp/ranges/view"><code>view</code></a> consisting of the sequence obtained from flattening a <a href="../ranges/view.html" title="cpp/ranges/view"><code>view</code></a> of <a href="../ranges/range.html" title="cpp/ranges/range"><code>range</code>s</a>  <br> <span class="t-mark">(class template)</span> <span class="t-mark">(range adaptor object)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../ranges/lazy_split_view.html" title="cpp/ranges/lazy split view"> <span class="t-lines"><span>ranges::lazy_split_view</span><span>views::lazy_split</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div></div>
</td>
<td>   a <a href="../ranges/view.html" title="cpp/ranges/view"><code>view</code></a> over the subranges obtained from splitting another <a href="../ranges/view.html" title="cpp/ranges/view"><code>view</code></a> using a delimiter  <br> <span class="t-mark">(class template)</span> <span class="t-mark">(range adaptor object)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../ranges/split_view.html" title="cpp/ranges/split view"> <span class="t-lines"><span>ranges::split_view</span><span>views::split</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div></div>
</td>
<td>   a <a href="../ranges/view.html" title="cpp/ranges/view"><code>view</code></a> over the subranges obtained from splitting another <a href="../ranges/view.html" title="cpp/ranges/view"><code>view</code></a> using a delimiter  <br> <span class="t-mark">(class template)</span> <span class="t-mark">(range adaptor object)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../ranges/view_counted.html" title="cpp/ranges/view counted"> <span class="t-lines"><span>views::counted</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div></div>
</td>
<td>   creates a subrange from an iterator and a count  <br> <span class="t-mark">(customization point object)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../ranges/common_view.html" title="cpp/ranges/common view"> <span class="t-lines"><span>ranges::common_view</span><span>views::common</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div></div>
</td>
<td>   converts a <a href="../ranges/view.html" title="cpp/ranges/view"><code>view</code></a> into a <a href="../ranges/common_range.html" title="cpp/ranges/common range"><code>common_range</code></a>  <br> <span class="t-mark">(class template)</span> <span class="t-mark">(range adaptor object)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../ranges/reverse_view.html" title="cpp/ranges/reverse view"> <span class="t-lines"><span>ranges::reverse_view</span><span>views::reverse</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div></div>
</td>
<td>   a <a href="../ranges/view.html" title="cpp/ranges/view"><code>view</code></a> that iterates over the elements of another bidirectional view in reverse order  <br> <span class="t-mark">(class template)</span> <span class="t-mark">(range adaptor object)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../ranges/as_const_view.html" title="cpp/ranges/as const view"> <span class="t-lines"><span>ranges::as_const_view</span><span>views::as_const</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx23">(C++23)</span></span></span></div></div>
</td>
<td>   converts a <a href="../ranges/view.html" title="cpp/ranges/view"><code>view</code></a> into a <a href="../ranges/constant_range.html" title="cpp/ranges/constant range"><code>constant_range</code></a>  <br> <span class="t-mark">(class template)</span> <span class="t-mark">(range adaptor object)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="https://en.cppreference.com/mwiki/index.php?title=cpp/ranges/as_rvalue_view&amp;action=edit&amp;redlink=1" class="new" title="cpp/ranges/as rvalue view (page does not exist)"> <span class="t-lines"><span>ranges::as_rvalue_view</span><span>views::as_rvalue</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx23">(C++23)</span></span></span></div></div>
</td>
<td>   a <a href="../ranges/view.html" title="cpp/ranges/view"><code>view</code></a> of a sequence that casts each element to an rvalue  <br> <span class="t-mark">(class template)</span> <span class="t-mark">(range adaptor object)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../ranges/elements_view.html" title="cpp/ranges/elements view"> <span class="t-lines"><span>ranges::elements_view</span><span>views::elements</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div></div>
</td>
<td>   takes a <a href="../ranges/view.html" title="cpp/ranges/view"><code>view</code></a> consisting of tuple-like values and a number N and produces a <a href="../ranges/view.html" title="cpp/ranges/view"><code>view</code></a> of N'th element of each tuple  <br> <span class="t-mark">(class template)</span> <span class="t-mark">(range adaptor object)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../ranges/keys_view.html" title="cpp/ranges/keys view"> <span class="t-lines"><span>ranges::keys_view</span><span>views::keys</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div></div>
</td>
<td>   takes a <a href="../ranges/view.html" title="cpp/ranges/view"><code>view</code></a> consisting of pair-like values and produces a <a href="../ranges/view.html" title="cpp/ranges/view"><code>view</code></a> of the first elements of each pair  <br> <span class="t-mark">(class template)</span> <span class="t-mark">(range adaptor object)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../ranges/values_view.html" title="cpp/ranges/values view"> <span class="t-lines"><span>ranges::values_view</span><span>views::values</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div></div>
</td>
<td>   takes a <a href="../ranges/view.html" title="cpp/ranges/view"><code>view</code></a> consisting of pair-like values and produces a <a href="../ranges/view.html" title="cpp/ranges/view"><code>view</code></a> of the second elements of each pair  <br> <span class="t-mark">(class template)</span> <span class="t-mark">(range adaptor object)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../ranges/zip_view.html" title="cpp/ranges/zip view"> <span class="t-lines"><span>ranges::zip_view</span><span>views::zip</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx23">(C++23)</span></span></span></div></div>
</td>
<td>   a <a href="../ranges/view.html" title="cpp/ranges/view"><code>view</code></a> consisting of tuples of references to corresponding elements of the adapted views <br> <span class="t-mark">(class template)</span> <span class="t-mark">(customization point object)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../ranges/zip_transform_view.html" title="cpp/ranges/zip transform view"> <span class="t-lines"><span>ranges::zip_transform_view</span><span>views::zip_transform</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx23">(C++23)</span></span></span></div></div>
</td>
<td>   a <a href="../ranges/view.html" title="cpp/ranges/view"><code>view</code></a> consisting of tuples of results of application of a transformation function to corresponding elements of the adapted views <br> <span class="t-mark">(class template)</span> <span class="t-mark">(customization point object)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="https://en.cppreference.com/mwiki/index.php?title=cpp/ranges/adjacent_view&amp;action=edit&amp;redlink=1" class="new" title="cpp/ranges/adjacent view (page does not exist)"> <span class="t-lines"><span>ranges::adjacent_view</span><span>views::adjacent</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx23">(C++23)</span></span></span></div></div>
</td>
<td>   a <a href="../ranges/view.html" title="cpp/ranges/view"><code>view</code></a> consisting of tuples of references to adjacent elements of the adapted view <br> <span class="t-mark">(class template)</span> <span class="t-mark">(range adaptor object)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="https://en.cppreference.com/mwiki/index.php?title=cpp/ranges/adjacent_transform_view&amp;action=edit&amp;redlink=1" class="new" title="cpp/ranges/adjacent transform view (page does not exist)"> <span class="t-lines"><span>ranges::adjacent_transform_view</span><span>views::adjacent_transform</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx23">(C++23)</span></span></span></div></div>
</td>
<td>   a <a href="../ranges/view.html" title="cpp/ranges/view"><code>view</code></a> consisting of tuples of results of application of a transformation function to adjacent elements of the adapted view <br> <span class="t-mark">(class template)</span> <span class="t-mark">(range adaptor object)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../ranges/join_with_view.html" title="cpp/ranges/join with view"> <span class="t-lines"><span>ranges::join_with_view</span><span>views::join_with</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx23">(C++23)</span></span></span></div></div>
</td>
<td>   a <a href="../ranges/view.html" title="cpp/ranges/view"><code>view</code></a> consisting of the sequence obtained from flattening a view of ranges, with the delimiter in between elements  <br> <span class="t-mark">(class template)</span> <span class="t-mark">(range adaptor object)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="https://en.cppreference.com/mwiki/index.php?title=cpp/ranges/cartesian_product_view&amp;action=edit&amp;redlink=1" class="new" title="cpp/ranges/cartesian product view (page does not exist)"> <span class="t-lines"><span>ranges::cartesian_product_view</span><span>views::cartesian_product</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx23">(C++23)</span></span></span></div></div>
</td>
<td>   a <a href="../ranges/view.html" title="cpp/ranges/view"><code>view</code></a> consisting of tuples of results calculated by the n-ary cartesian product of the adapted views  <br> <span class="t-mark">(class template)</span> <span class="t-mark">(customization point object)</span> </td></tr>


<tr>
<td colspan="2"> <h3> <span class="mw-headline" id="Customization_point_objects"> Customization point objects</span></h3>
</td></tr>

<tr>
<td colspan="2"> <h5> <span class="mw-headline" id="Range_access">  Range access </span></h5>
</td></tr>

<tr class="t-dsc-header">
<td colspan="2"> <div>Defined in  namespace <code>std::ranges</code> </div>
</td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../ranges/begin.html" title="cpp/ranges/begin"> <span class="t-lines"><span>ranges::begin</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div></div>
</td>
<td>  returns an iterator to the beginning of a range  <br> <span class="t-mark">(customization point object)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../ranges/end.html" title="cpp/ranges/end"> <span class="t-lines"><span>ranges::end</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div></div>
</td>
<td>  returns a sentinel indicating the end of a range  <br> <span class="t-mark">(customization point object)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../ranges/cbegin.html" title="cpp/ranges/cbegin"> <span class="t-lines"><span>ranges::cbegin</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div></div>
</td>
<td>  returns an iterator to the beginning of a read-only range  <br> <span class="t-mark">(customization point object)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../ranges/cend.html" title="cpp/ranges/cend"> <span class="t-lines"><span>ranges::cend</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div></div>
</td>
<td>  returns a sentinel indicating the end of a read-only range  <br> <span class="t-mark">(customization point object)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../ranges/rbegin.html" title="cpp/ranges/rbegin"> <span class="t-lines"><span>ranges::rbegin</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div></div>
</td>
<td>  returns a reverse iterator to a range  <br> <span class="t-mark">(customization point object)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../ranges/rend.html" title="cpp/ranges/rend"> <span class="t-lines"><span>ranges::rend</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div></div>
</td>
<td>  returns a reverse end iterator to a range  <br> <span class="t-mark">(customization point object)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../ranges/crbegin.html" title="cpp/ranges/crbegin"> <span class="t-lines"><span>ranges::crbegin</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div></div>
</td>
<td>  returns a reverse iterator to a read-only range  <br> <span class="t-mark">(customization point object)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../ranges/crend.html" title="cpp/ranges/crend"> <span class="t-lines"><span>ranges::crend</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div></div>
</td>
<td>  returns a reverse end iterator to a read-only range  <br> <span class="t-mark">(customization point object)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../ranges/size.html" title="cpp/ranges/size"> <span class="t-lines"><span>ranges::size</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div></div>
</td>
<td>  returns an integer equal to the size of a range  <br> <span class="t-mark">(customization point object)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../ranges/ssize.html" title="cpp/ranges/ssize"> <span class="t-lines"><span>ranges::ssize</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div></div>
</td>
<td>  returns a signed integer equal to the size of a range  <br> <span class="t-mark">(customization point object)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../ranges/empty.html" title="cpp/ranges/empty"> <span class="t-lines"><span>ranges::empty</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div></div>
</td>
<td>   checks whether a range is empty  <br> <span class="t-mark">(customization point object)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../ranges/data.html" title="cpp/ranges/data"> <span class="t-lines"><span>ranges::data</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div></div>
</td>
<td>  obtains a pointer to the beginning of a contiguous range  <br> <span class="t-mark">(customization point object)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../ranges/cdata.html" title="cpp/ranges/cdata"> <span class="t-lines"><span>ranges::cdata</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div></div>
</td>
<td>  obtains a pointer to the beginning of a read-only contiguous range  <br> <span class="t-mark">(customization point object)</span> </td></tr>


<tr>
<td colspan="2"> <h3> <span class="mw-headline" id="Enumerations"> Enumerations</span></h3>
</td></tr>

<tr class="t-dsc-header">
<td colspan="2"> <div>Defined in  namespace <code>std::ranges</code> </div>
</td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../ranges/subrange_kind.html" title="cpp/ranges/subrange kind"> <span class="t-lines"><span>ranges::subrange_kind</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div></div>
</td>
<td>   specifies whether a <span class="t-lc"><a href="../ranges/subrange.html" title="cpp/ranges/subrange">std::ranges::subrange</a></span> models <span class="t-lc"><a href="../ranges/sized_range.html" title="cpp/ranges/sized range">std::ranges::sized_range</a></span>  <br> <span class="t-mark">(enum)</span> </td></tr>


<tr>
<td colspan="2"> <h3> <span class="mw-headline" id="Helpers"> Helpers</span></h3>
</td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../ranges/subrange/tuple_size.html" title="cpp/ranges/subrange/tuple size"> <span class="t-lines"><span>std::tuple_size<span class="t-dsc-small">&lt;std::ranges::subrange&gt;</span></span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div></div>
</td>
<td>   obtains the number of components of a <span class="t-lc"><a href="../ranges/subrange.html" title="cpp/ranges/subrange">std::ranges::subrange</a></span>  <br> <span class="t-mark">(class template specialization)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../ranges/subrange/tuple_element.html" title="cpp/ranges/subrange/tuple element"> <span class="t-lines"><span>std::tuple_element<span class="t-dsc-small">&lt;std::ranges::subrange&gt;</span></span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div></div>
</td>
<td>   obtains the type of the iterator or the sentinel of a <span class="t-lc"><a href="../ranges/subrange.html" title="cpp/ranges/subrange">std::ranges::subrange</a></span>  <br> <span class="t-mark">(class template specialization)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../ranges/from_range.html" title="cpp/ranges/from range"> <span class="t-lines"><span>from_range_t</span><span>from_range</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx23">(C++23)</span></span></span></div></div>
</td>
<td>   from-range construction tag <br> <span class="t-mark">(class)</span> <span class="t-mark">(constant)</span> </td></tr>
</table>
<h3><span class="mw-headline" id="Synopsis">Synopsis</span></h3>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="co2">#include &lt;compare&gt;</span>
<span class="co2">#include &lt;initializer_list&gt;</span>
<span class="co2">#include &lt;iterator&gt;</span>
 
<span class="kw1">namespace</span> std<span class="sy4">::</span><span class="me2">ranges</span> <span class="br0">{</span>
  <span class="kw1">inline</span> <span class="kw1">namespace</span> <span class="coMULTI">/* unspecified */</span> <span class="br0">{</span>
    <span class="co1">// range access</span>
    <span class="kw1">inline</span> <span class="kw4">constexpr</span> <span class="coMULTI">/* unspecified */</span> begin   <span class="sy1">=</span> <span class="coMULTI">/* unspecified */</span><span class="sy4">;</span>
    <span class="kw1">inline</span> <span class="kw4">constexpr</span> <span class="coMULTI">/* unspecified */</span> end     <span class="sy1">=</span> <span class="coMULTI">/* unspecified */</span><span class="sy4">;</span>
    <span class="kw1">inline</span> <span class="kw4">constexpr</span> <span class="coMULTI">/* unspecified */</span> cbegin  <span class="sy1">=</span> <span class="coMULTI">/* unspecified */</span><span class="sy4">;</span>
    <span class="kw1">inline</span> <span class="kw4">constexpr</span> <span class="coMULTI">/* unspecified */</span> cend    <span class="sy1">=</span> <span class="coMULTI">/* unspecified */</span><span class="sy4">;</span>
    <span class="kw1">inline</span> <span class="kw4">constexpr</span> <span class="coMULTI">/* unspecified */</span> rbegin  <span class="sy1">=</span> <span class="coMULTI">/* unspecified */</span><span class="sy4">;</span>
    <span class="kw1">inline</span> <span class="kw4">constexpr</span> <span class="coMULTI">/* unspecified */</span> rend    <span class="sy1">=</span> <span class="coMULTI">/* unspecified */</span><span class="sy4">;</span>
    <span class="kw1">inline</span> <span class="kw4">constexpr</span> <span class="coMULTI">/* unspecified */</span> crbegin <span class="sy1">=</span> <span class="coMULTI">/* unspecified */</span><span class="sy4">;</span>
    <span class="kw1">inline</span> <span class="kw4">constexpr</span> <span class="coMULTI">/* unspecified */</span> crend   <span class="sy1">=</span> <span class="coMULTI">/* unspecified */</span><span class="sy4">;</span>
 
    <span class="kw1">inline</span> <span class="kw4">constexpr</span> <span class="coMULTI">/* unspecified */</span> size    <span class="sy1">=</span> <span class="coMULTI">/* unspecified */</span><span class="sy4">;</span>
    <span class="kw1">inline</span> <span class="kw4">constexpr</span> <span class="coMULTI">/* unspecified */</span> ssize   <span class="sy1">=</span> <span class="coMULTI">/* unspecified */</span><span class="sy4">;</span>
    <span class="kw1">inline</span> <span class="kw4">constexpr</span> <span class="coMULTI">/* unspecified */</span> empty   <span class="sy1">=</span> <span class="coMULTI">/* unspecified */</span><span class="sy4">;</span>
    <span class="kw1">inline</span> <span class="kw4">constexpr</span> <span class="coMULTI">/* unspecified */</span> data    <span class="sy1">=</span> <span class="coMULTI">/* unspecified */</span><span class="sy4">;</span>
    <span class="kw1">inline</span> <span class="kw4">constexpr</span> <span class="coMULTI">/* unspecified */</span> cdata   <span class="sy1">=</span> <span class="coMULTI">/* unspecified */</span><span class="sy4">;</span>
  <span class="br0">}</span>
 
  <span class="co1">// ranges</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> T<span class="sy1">&gt;</span>
    concept range <span class="sy1">=</span> <span class="coMULTI">/* see description */</span><span class="sy4">;</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> T<span class="sy1">&gt;</span>
    <span class="kw1">inline</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> enable_borrowed_range <span class="sy1">=</span> <span class="kw2">false</span><span class="sy4">;</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> T<span class="sy1">&gt;</span>
    concept borrowed_range <span class="sy1">=</span> <span class="coMULTI">/* see description */</span><span class="sy4">;</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> T<span class="sy1">&gt;</span>
    <span class="kw1">using</span> iterator_t <span class="sy1">=</span> decltype<span class="br0">(</span><a href="../../../http:/en.cppreference.com/w/cpp/ranges-ranges-placeholder/begin"><span class="kw2885">ranges::<span class="me2">begin</span></span></a><span class="br0">(</span>declval<span class="sy1">&lt;</span>T<span class="sy3">&amp;</span><span class="sy1">&gt;</span><span class="br0">(</span><span class="br0">)</span><span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span>range R<span class="sy1">&gt;</span>
    <span class="kw1">using</span> sentinel_t <span class="sy1">=</span> decltype<span class="br0">(</span><a href="../../../http:/en.cppreference.com/w/cpp/ranges-ranges-placeholder/end"><span class="kw2887">ranges::<span class="me2">end</span></span></a><span class="br0">(</span>declval<span class="sy1">&lt;</span>R<span class="sy3">&amp;</span><span class="sy1">&gt;</span><span class="br0">(</span><span class="br0">)</span><span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span>range R<span class="sy1">&gt;</span>
    <span class="kw1">using</span> range_difference_t <span class="sy1">=</span> iter_difference_t<span class="sy1">&lt;</span>iterator_t<span class="sy1">&lt;</span>R<span class="sy1">&gt;&gt;</span><span class="sy4">;</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span>sized_range R<span class="sy1">&gt;</span>
    <span class="kw1">using</span> range_size_t <span class="sy1">=</span> decltype<span class="br0">(</span><a href="../ranges/size.html"><span class="kw3103">ranges::<span class="me2">size</span></span></a><span class="br0">(</span>declval<span class="sy1">&lt;</span>R<span class="sy3">&amp;</span><span class="sy1">&gt;</span><span class="br0">(</span><span class="br0">)</span><span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span>range R<span class="sy1">&gt;</span>
    <span class="kw1">using</span> range_value_t <span class="sy1">=</span> iter_value_t<span class="sy1">&lt;</span>iterator_t<span class="sy1">&lt;</span>R<span class="sy1">&gt;&gt;</span><span class="sy4">;</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span>range R<span class="sy1">&gt;</span>
    <span class="kw1">using</span> range_reference_t <span class="sy1">=</span> iter_reference_t<span class="sy1">&lt;</span>iterator_t<span class="sy1">&lt;</span>R<span class="sy1">&gt;&gt;</span><span class="sy4">;</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span>range R<span class="sy1">&gt;</span>
    <span class="kw1">using</span> range_rvalue_reference_t <span class="sy1">=</span> iter_rvalue_reference_t<span class="sy1">&lt;</span>iterator_t<span class="sy1">&lt;</span>R<span class="sy1">&gt;&gt;</span><span class="sy4">;</span>
 
  <span class="co1">// sized ranges</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span><span class="sy1">&gt;</span>
    <span class="kw1">inline</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> disable_sized_range <span class="sy1">=</span> <span class="kw2">false</span><span class="sy4">;</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> T<span class="sy1">&gt;</span>
    concept sized_range <span class="sy1">=</span> <span class="coMULTI">/* see description */</span><span class="sy4">;</span>
 
  <span class="co1">// views</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> T<span class="sy1">&gt;</span>
    <span class="kw1">inline</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> enable_view <span class="sy1">=</span> <span class="coMULTI">/* see description */</span><span class="sy4">;</span>
 
  <span class="kw1">struct</span> view_base <span class="br0">{</span><span class="br0">}</span><span class="sy4">;</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> T<span class="sy1">&gt;</span>
    concept view <span class="sy1">=</span> <span class="coMULTI">/* see description */</span><span class="sy4">;</span>
 
  <span class="co1">// other range refinements</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> R, <span class="kw1">class</span> T<span class="sy1">&gt;</span>
    concept output_range <span class="sy1">=</span> <span class="coMULTI">/* see description */</span><span class="sy4">;</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> T<span class="sy1">&gt;</span>
    concept input_range <span class="sy1">=</span> <span class="coMULTI">/* see description */</span><span class="sy4">;</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> T<span class="sy1">&gt;</span>
    concept forward_range <span class="sy1">=</span> <span class="coMULTI">/* see description */</span><span class="sy4">;</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> T<span class="sy1">&gt;</span>
    concept bidirectional_range <span class="sy1">=</span> <span class="coMULTI">/* see description */</span><span class="sy4">;</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> T<span class="sy1">&gt;</span>
    concept random_access_range <span class="sy1">=</span> <span class="coMULTI">/* see description */</span><span class="sy4">;</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> T<span class="sy1">&gt;</span>
    concept contiguous_range <span class="sy1">=</span> <span class="coMULTI">/* see description */</span><span class="sy4">;</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> T<span class="sy1">&gt;</span>
    concept common_range <span class="sy1">=</span> <span class="coMULTI">/* see description */</span><span class="sy4">;</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> T<span class="sy1">&gt;</span>
    concept viewable_range <span class="sy1">=</span> <span class="coMULTI">/* see description */</span><span class="sy4">;</span>
 
  <span class="co1">// class template view_interface</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> D<span class="sy1">&gt;</span>
    requires is_class_v<span class="sy1">&lt;</span>D<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> same_as<span class="sy1">&lt;</span>D, remove_cv_t<span class="sy1">&lt;</span>D<span class="sy1">&gt;&gt;</span>
  <span class="kw1">class</span> view_interface<span class="sy4">;</span>
 
  <span class="co1">// sub-ranges</span>
  <span class="kw2">enum</span> <span class="kw1">class</span> subrange_kind <span class="sy4">:</span> <span class="kw4">bool</span> <span class="br0">{</span> unsized, sized <span class="br0">}</span><span class="sy4">;</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span>input_or_output_iterator I, sentinel_for<span class="sy1">&lt;</span>I<span class="sy1">&gt;</span> S <span class="sy1">=</span> I, subrange_kind K <span class="sy1">=</span>
      sized_sentinel_for<span class="sy1">&lt;</span>S, I<span class="sy1">&gt;</span> <span class="sy4">?</span> subrange_kind<span class="sy4">::</span><span class="me2">sized</span> <span class="sy4">:</span> subrange_kind<span class="sy4">::</span><span class="me2">unsized</span><span class="sy1">&gt;</span>
    requires <span class="br0">(</span>K <span class="sy1">==</span> subrange_kind<span class="sy4">::</span><span class="me2">sized</span> <span class="sy3">||</span> <span class="sy3">!</span>sized_sentinel_for<span class="sy1">&lt;</span>S, I<span class="sy1">&gt;</span><span class="br0">)</span>
  <span class="kw1">class</span> subrange<span class="sy4">;</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> I, <span class="kw1">class</span> S, subrange_kind K<span class="sy1">&gt;</span>
    <span class="kw1">inline</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> enable_borrowed_range<span class="sy1">&lt;</span>subrange<span class="sy1">&lt;</span>I, S, K<span class="sy1">&gt;&gt;</span> <span class="sy1">=</span> <span class="kw2">true</span><span class="sy4">;</span>
 
  <span class="co1">// dangling iterator handling</span>
  <span class="kw1">struct</span> dangling<span class="sy4">;</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span>range R<span class="sy1">&gt;</span>
    <span class="kw1">using</span> borrowed_iterator_t <span class="sy1">=</span> <span class="coMULTI">/* see description */</span><span class="sy4">;</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span>range R<span class="sy1">&gt;</span>
    <span class="kw1">using</span> borrowed_subrange_t <span class="sy1">=</span> <span class="coMULTI">/* see description */</span><span class="sy4">;</span>
 
  <span class="co1">// range conversions</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> C, input_range R, <span class="kw1">class</span>... <span class="me1">Args</span><span class="sy1">&gt;</span> requires <span class="br0">(</span><span class="sy3">!</span>view<span class="sy1">&lt;</span>C<span class="sy1">&gt;</span><span class="br0">)</span>
    <span class="kw4">constexpr</span> C to<span class="br0">(</span>R<span class="sy3">&amp;&amp;</span> r, Args<span class="sy3">&amp;&amp;</span>... <span class="me1">args</span><span class="br0">)</span><span class="sy4">;</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span>...<span class="sy1">&gt;</span> <span class="kw1">class</span> C, input_range R, <span class="kw1">class</span>... <span class="me1">Args</span><span class="sy1">&gt;</span>
    <span class="kw4">constexpr</span> <span class="kw4">auto</span> to<span class="br0">(</span>R<span class="sy3">&amp;&amp;</span> r, Args<span class="sy3">&amp;&amp;</span>... <span class="me1">args</span><span class="br0">)</span> <span class="sy2">-</span><span class="sy1">&gt;</span> <span class="coMULTI">/* see description */</span><span class="sy4">;</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> C, <span class="kw1">class</span>... <span class="me1">Args</span><span class="sy1">&gt;</span> requires <span class="br0">(</span><span class="sy3">!</span>view<span class="sy1">&lt;</span>C<span class="sy1">&gt;</span><span class="br0">)</span>
    <span class="kw4">constexpr</span> <span class="kw4">auto</span> to<span class="br0">(</span>Args<span class="sy3">&amp;&amp;</span>... <span class="me1">args</span><span class="br0">)</span> <span class="sy2">-</span><span class="sy1">&gt;</span> <span class="coMULTI">/* see description */</span><span class="sy4">;</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span>...<span class="sy1">&gt;</span> <span class="kw1">class</span> C, <span class="kw1">class</span>... <span class="me1">Args</span><span class="sy1">&gt;</span>
    <span class="kw4">constexpr</span> <span class="kw4">auto</span> to<span class="br0">(</span>Args<span class="sy3">&amp;&amp;</span>... <span class="me1">args</span><span class="br0">)</span> <span class="sy2">-</span><span class="sy1">&gt;</span> <span class="coMULTI">/* see description */</span><span class="sy4">;</span>
 
  <span class="co1">// empty view</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> T<span class="sy1">&gt;</span>
    requires is_object_v<span class="sy1">&lt;</span>T<span class="sy1">&gt;</span>
  <span class="kw1">class</span> empty_view<span class="sy4">;</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> T<span class="sy1">&gt;</span>
    <span class="kw1">inline</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> enable_borrowed_range<span class="sy1">&lt;</span>empty_view<span class="sy1">&lt;</span>T<span class="sy1">&gt;&gt;</span> <span class="sy1">=</span> <span class="kw2">true</span><span class="sy4">;</span>
 
  <span class="kw1">namespace</span> views <span class="br0">{</span>
    <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> T<span class="sy1">&gt;</span>
      <span class="kw1">inline</span> <span class="kw4">constexpr</span> empty_view<span class="sy1">&lt;</span>T<span class="sy1">&gt;</span> empty<span class="br0">{</span><span class="br0">}</span><span class="sy4">;</span>
  <span class="br0">}</span>
 
  <span class="co1">// single view</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span>copy_constructible T<span class="sy1">&gt;</span>
    requires is_object_v<span class="sy1">&lt;</span>T<span class="sy1">&gt;</span>
  <span class="kw1">class</span> single_view<span class="sy4">;</span>
 
  <span class="kw1">namespace</span> views <span class="br0">{</span> <span class="kw1">inline</span> <span class="kw4">constexpr</span> <span class="coMULTI">/* unspecified */</span> single <span class="sy1">=</span> <span class="coMULTI">/* unspecified */</span><span class="sy4">;</span> <span class="br0">}</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw4">bool</span> Const, <span class="kw1">class</span> T<span class="sy1">&gt;</span>
    <span class="kw1">using</span> <span class="coMULTI">/*maybe-const*/</span> <span class="sy1">=</span> conditional_t<span class="sy1">&lt;</span>Const, <span class="kw4">const</span> T, T<span class="sy1">&gt;</span><span class="sy4">;</span>   <span class="co1">// exposition only</span>
 
  <span class="co1">// iota view</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span>weakly_incrementable W, semiregular Bound <span class="sy1">=</span> unreachable_sentinel_t<span class="sy1">&gt;</span>
    requires <span class="coMULTI">/*weakly-equality-comparable-with*/</span><span class="sy1">&lt;</span>W, Bound<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> copyable<span class="sy1">&lt;</span>W<span class="sy1">&gt;</span>
  <span class="kw1">class</span> iota_view<span class="sy4">;</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> W, <span class="kw1">class</span> Bound<span class="sy1">&gt;</span>
    <span class="kw1">inline</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> enable_borrowed_range<span class="sy1">&lt;</span>iota_view<span class="sy1">&lt;</span>W, Bound<span class="sy1">&gt;&gt;</span> <span class="sy1">=</span> <span class="kw2">true</span><span class="sy4">;</span>
 
  <span class="kw1">namespace</span> views <span class="br0">{</span> <span class="kw1">inline</span> <span class="kw4">constexpr</span> <span class="coMULTI">/* unspecified */</span> iota <span class="sy1">=</span> <span class="coMULTI">/* unspecified */</span><span class="sy4">;</span> <span class="br0">}</span>
 
  <span class="co1">// istream view</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span>movable Val, <span class="kw1">class</span> CharT, <span class="kw1">class</span> Traits <span class="sy1">=</span> char_traits<span class="sy1">&lt;</span>CharT<span class="sy1">&gt;&gt;</span>
    requires <span class="coMULTI">/* see description */</span>
  <span class="kw1">class</span> basic_istream_view<span class="sy4">;</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> Val<span class="sy1">&gt;</span>
    <span class="kw1">using</span> istream_view <span class="sy1">=</span> basic_istream_view<span class="sy1">&lt;</span>Val, <span class="kw4">char</span><span class="sy1">&gt;</span><span class="sy4">;</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> Val<span class="sy1">&gt;</span>
    <span class="kw1">using</span> wistream_view <span class="sy1">=</span> basic_istream_view<span class="sy1">&lt;</span>Val, <span class="kw4">wchar_t</span><span class="sy1">&gt;</span><span class="sy4">;</span>
 
  <span class="kw1">namespace</span> views <span class="br0">{</span> <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> T<span class="sy1">&gt;</span>
      <span class="kw1">inline</span> <span class="kw4">constexpr</span> <span class="coMULTI">/* unspecified */</span> istream <span class="sy1">=</span> <span class="coMULTI">/* unspecified */</span><span class="sy4">;</span> <span class="br0">}</span>
 
  <span class="co1">// range adaptor objects</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> D<span class="sy1">&gt;</span>
    requires is_class_v<span class="sy1">&lt;</span>D<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> same_as<span class="sy1">&lt;</span>D, remove_cv_t<span class="sy1">&lt;</span>D<span class="sy1">&gt;&gt;</span>
  <span class="kw1">class</span> range_adaptor_closure <span class="br0">{</span> <span class="br0">}</span><span class="sy4">;</span>
 
  <span class="co1">// all view</span>
  <span class="kw1">namespace</span> views <span class="br0">{</span>
    <span class="kw1">inline</span> <span class="kw4">constexpr</span> <span class="coMULTI">/* unspecified */</span> all <span class="sy1">=</span> <span class="coMULTI">/* unspecified */</span><span class="sy4">;</span>
 
    <span class="kw1">template</span><span class="sy1">&lt;</span>viewable_range R<span class="sy1">&gt;</span>
      <span class="kw1">using</span> all_t <span class="sy1">=</span> decltype<span class="br0">(</span>all<span class="br0">(</span>declval<span class="sy1">&lt;</span>R<span class="sy1">&gt;</span><span class="br0">(</span><span class="br0">)</span><span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
  <span class="br0">}</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span>range R<span class="sy1">&gt;</span>
    requires is_object_v<span class="sy1">&lt;</span>R<span class="sy1">&gt;</span>
  <span class="kw1">class</span> ref_view<span class="sy4">;</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> T<span class="sy1">&gt;</span>
    <span class="kw1">inline</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> enable_borrowed_range<span class="sy1">&lt;</span>ref_view<span class="sy1">&lt;</span>T<span class="sy1">&gt;&gt;</span> <span class="sy1">=</span> <span class="kw2">true</span><span class="sy4">;</span>
 
  <span class="co1">// owning view</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span>range R<span class="sy1">&gt;</span>
    requires <span class="coMULTI">/* see description */</span>
  <span class="kw1">class</span> owning_view<span class="sy4">;</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> T<span class="sy1">&gt;</span>
    <span class="kw1">inline</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> enable_borrowed_range<span class="sy1">&lt;</span>owning_view<span class="sy1">&lt;</span>T<span class="sy1">&gt;&gt;</span> <span class="sy1">=</span>
      enable_borrowed_range<span class="sy1">&lt;</span>T<span class="sy1">&gt;</span><span class="sy4">;</span>
 
  <span class="co1">// filter view</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span>input_range V, indirect_unary_predicate<span class="sy1">&lt;</span>iterator_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;&gt;</span> Pred<span class="sy1">&gt;</span>
    requires view<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> is_object_v<span class="sy1">&lt;</span>Pred<span class="sy1">&gt;</span>
  <span class="kw1">class</span> filter_view<span class="sy4">;</span>
 
  <span class="kw1">namespace</span> views <span class="br0">{</span> <span class="kw1">inline</span> <span class="kw4">constexpr</span> <span class="coMULTI">/* unspecified */</span> filter <span class="sy1">=</span> <span class="coMULTI">/* unspecified */</span><span class="sy4">;</span> <span class="br0">}</span>
 
  <span class="co1">// transform view</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span>input_range V, copy_constructible F<span class="sy1">&gt;</span>
    requires view<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> is_object_v<span class="sy1">&lt;</span>F<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
             regular_invocable<span class="sy1">&lt;</span>F<span class="sy3">&amp;</span>, range_reference_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;&gt;</span> <span class="sy3">&amp;&amp;</span>
             <span class="coMULTI">/*can-reference*/</span><span class="sy1">&lt;</span>invoke_result_t<span class="sy1">&lt;</span>F<span class="sy3">&amp;</span>, range_reference_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;&gt;&gt;</span>
  <span class="kw1">class</span> transform_view<span class="sy4">;</span>
 
  <span class="kw1">namespace</span> views <span class="br0">{</span> <span class="kw1">inline</span> <span class="kw4">constexpr</span> <span class="coMULTI">/* unspecified */</span> transform <span class="sy1">=</span> <span class="coMULTI">/* unspecified */</span><span class="sy4">;</span> <span class="br0">}</span>
 
  <span class="co1">// take view</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span>view<span class="sy1">&gt;</span> <span class="kw1">class</span> take_view<span class="sy4">;</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> T<span class="sy1">&gt;</span>
    <span class="kw1">inline</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> enable_borrowed_range<span class="sy1">&lt;</span>take_view<span class="sy1">&lt;</span>T<span class="sy1">&gt;&gt;</span> <span class="sy1">=</span> enable_borrowed_range<span class="sy1">&lt;</span>T<span class="sy1">&gt;</span><span class="sy4">;</span>
 
  <span class="kw1">namespace</span> views <span class="br0">{</span> <span class="kw1">inline</span> <span class="kw4">constexpr</span> <span class="coMULTI">/* unspecified */</span> take <span class="sy1">=</span> <span class="coMULTI">/* unspecified */</span><span class="sy4">;</span> <span class="br0">}</span>
 
  <span class="co1">// take while view</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span>view V, <span class="kw1">class</span> Pred<span class="sy1">&gt;</span>
    requires input_range<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> is_object_v<span class="sy1">&lt;</span>Pred<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
             indirect_unary_predicate<span class="sy1">&lt;</span><span class="kw4">const</span> Pred, iterator_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;&gt;</span>
    <span class="kw1">class</span> take_while_view<span class="sy4">;</span>
 
  <span class="kw1">namespace</span> views <span class="br0">{</span> <span class="kw1">inline</span> <span class="kw4">constexpr</span> <span class="coMULTI">/* unspecified */</span> take_while <span class="sy1">=</span> <span class="coMULTI">/* unspecified */</span><span class="sy4">;</span> <span class="br0">}</span>
 
  <span class="co1">// drop view</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span>view V<span class="sy1">&gt;</span>
    <span class="kw1">class</span> drop_view<span class="sy4">;</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> T<span class="sy1">&gt;</span>
    <span class="kw1">inline</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> enable_borrowed_range<span class="sy1">&lt;</span>drop_view<span class="sy1">&lt;</span>T<span class="sy1">&gt;&gt;</span> <span class="sy1">=</span> enable_borrowed_range<span class="sy1">&lt;</span>T<span class="sy1">&gt;</span><span class="sy4">;</span>
 
  <span class="kw1">namespace</span> views <span class="br0">{</span> <span class="kw1">inline</span> <span class="kw4">constexpr</span> <span class="coMULTI">/* unspecified */</span> drop <span class="sy1">=</span> <span class="coMULTI">/* unspecified */</span><span class="sy4">;</span> <span class="br0">}</span>
 
  <span class="co1">// drop while view</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span>view V, <span class="kw1">class</span> Pred<span class="sy1">&gt;</span>
    requires input_range<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> is_object_v<span class="sy1">&lt;</span>Pred<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
             indirect_unary_predicate<span class="sy1">&lt;</span><span class="kw4">const</span> Pred, iterator_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;&gt;</span>
    <span class="kw1">class</span> drop_while_view<span class="sy4">;</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> T, <span class="kw1">class</span> Pred<span class="sy1">&gt;</span>
    <span class="kw1">inline</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> enable_borrowed_range<span class="sy1">&lt;</span>drop_while_view<span class="sy1">&lt;</span>T, Pred<span class="sy1">&gt;&gt;</span> <span class="sy1">=</span>
      enable_borrowed_range<span class="sy1">&lt;</span>T<span class="sy1">&gt;</span><span class="sy4">;</span>
 
  <span class="kw1">namespace</span> views <span class="br0">{</span> <span class="kw1">inline</span> <span class="kw4">constexpr</span> <span class="coMULTI">/* unspecified */</span> drop_while <span class="sy1">=</span> <span class="coMULTI">/* unspecified */</span><span class="sy4">;</span> <span class="br0">}</span>
 
  <span class="co1">// join view</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span>input_range V<span class="sy1">&gt;</span>
    requires view<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> input_range<span class="sy1">&lt;</span>range_reference_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;&gt;</span>
  <span class="kw1">class</span> join_view<span class="sy4">;</span>
 
  <span class="kw1">namespace</span> views <span class="br0">{</span> <span class="kw1">inline</span> <span class="kw4">constexpr</span> <span class="coMULTI">/* unspecified */</span> join <span class="sy1">=</span> <span class="coMULTI">/* unspecified */</span><span class="sy4">;</span> <span class="br0">}</span>
 
  <span class="co1">// join with view</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> R, <span class="kw1">class</span> P<span class="sy1">&gt;</span>
    concept <span class="coMULTI">/*compatible-joinable-ranges*/</span> <span class="sy1">=</span> <span class="coMULTI">/* see description */</span><span class="sy4">;</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span>input_range V, forward_range Pattern<span class="sy1">&gt;</span>
    requires view<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> input_range<span class="sy1">&lt;</span>range_reference_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;&gt;</span>
          <span class="sy3">&amp;&amp;</span> view<span class="sy1">&lt;</span>Pattern<span class="sy1">&gt;</span>
          <span class="sy3">&amp;&amp;</span> <span class="coMULTI">/*compatible-joinable-ranges*/</span><span class="sy1">&lt;</span>range_reference_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span>, Pattern<span class="sy1">&gt;</span>
  <span class="kw1">class</span> join_with_view<span class="sy4">;</span>
 
  <span class="kw1">namespace</span> view <span class="br0">{</span> <span class="kw1">inline</span> <span class="kw4">constexpr</span> <span class="coMULTI">/* unspecified */</span> join_with <span class="sy1">=</span> <span class="coMULTI">/* unspecified */</span><span class="sy4">;</span> <span class="br0">}</span>
 
  <span class="co1">// lazy split view</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> R<span class="sy1">&gt;</span>
    concept <span class="coMULTI">/*tiny-range*/</span> <span class="sy1">=</span> <span class="coMULTI">/* see description */</span><span class="sy4">;</span>   <span class="co1">// exposition only</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span>input_range V, forward_range Pattern<span class="sy1">&gt;</span>
    requires view<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> view<span class="sy1">&lt;</span>Pattern<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
             indirectly_comparable<span class="sy1">&lt;</span>iterator_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span>, iterator_t<span class="sy1">&lt;</span>Pattern<span class="sy1">&gt;</span>, <a href="../functional/ranges/equal_to.html"><span class="kw2844">ranges::<span class="me2">equal_to</span></span></a><span class="sy1">&gt;</span>
             <span class="sy3">&amp;&amp;</span> <span class="br0">(</span>forward_range<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> <span class="sy3">||</span> <span class="coMULTI">/*tiny-range*/</span><span class="sy1">&lt;</span>Pattern<span class="sy1">&gt;</span><span class="br0">)</span>
  <span class="kw1">class</span> lazy_split_view<span class="sy4">;</span>
 
  <span class="co1">// split view</span>
 <span class="kw1">template</span><span class="sy1">&lt;</span>forward_range V, forward_range Pattern<span class="sy1">&gt;</span>
   requires view<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> view<span class="sy1">&lt;</span>Pattern<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
            indirectly_comparable<span class="sy1">&lt;</span>iterator_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span>, iterator_t<span class="sy1">&lt;</span>Pattern<span class="sy1">&gt;</span>, <a href="../functional/ranges/equal_to.html"><span class="kw2844">ranges::<span class="me2">equal_to</span></span></a><span class="sy1">&gt;</span>
  <span class="kw1">class</span> split_view<span class="sy4">;</span>
 
  <span class="kw1">namespace</span> views <span class="br0">{</span>
    <span class="kw1">inline</span> <span class="kw4">constexpr</span> <span class="coMULTI">/* unspecified */</span> lazy_split <span class="sy1">=</span> <span class="coMULTI">/* unspecified */</span><span class="sy4">;</span>
    <span class="kw1">inline</span> <span class="kw4">constexpr</span> <span class="coMULTI">/* unspecified */</span> split <span class="sy1">=</span> <span class="coMULTI">/* unspecified */</span><span class="sy4">;</span>
  <span class="br0">}</span>
 
  <span class="co1">// counted view</span>
  <span class="kw1">namespace</span> views <span class="br0">{</span> <span class="kw1">inline</span> <span class="kw4">constexpr</span> <span class="coMULTI">/* unspecified */</span> counted <span class="sy1">=</span> <span class="coMULTI">/* unspecified */</span><span class="sy4">;</span> <span class="br0">}</span>
 
  <span class="co1">// common view</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span>view V<span class="sy1">&gt;</span>
    requires <span class="br0">(</span><span class="sy3">!</span>common_range<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> copyable<span class="sy1">&lt;</span>iterator_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;&gt;</span><span class="br0">)</span>
  <span class="kw1">class</span> common_view<span class="sy4">;</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> T<span class="sy1">&gt;</span>
    <span class="kw1">inline</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> enable_borrowed_range<span class="sy1">&lt;</span>common_view<span class="sy1">&lt;</span>T<span class="sy1">&gt;&gt;</span> <span class="sy1">=</span>
      enable_borrowed_range<span class="sy1">&lt;</span>T<span class="sy1">&gt;</span><span class="sy4">;</span>
 
  <span class="kw1">namespace</span> views <span class="br0">{</span> <span class="kw1">inline</span> <span class="kw4">constexpr</span> <span class="coMULTI">/* unspecified */</span> common <span class="sy1">=</span> <span class="coMULTI">/* unspecified */</span><span class="sy4">;</span> <span class="br0">}</span>
 
  <span class="co1">// reverse view</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span>view V<span class="sy1">&gt;</span>
    requires bidirectional_range<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span>
  <span class="kw1">class</span> reverse_view<span class="sy4">;</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> T<span class="sy1">&gt;</span>
    <span class="kw1">inline</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> enable_borrowed_range<span class="sy1">&lt;</span>reverse_view<span class="sy1">&lt;</span>T<span class="sy1">&gt;&gt;</span> <span class="sy1">=</span>
      enable_borrowed_range<span class="sy1">&lt;</span>T<span class="sy1">&gt;</span><span class="sy4">;</span>
 
  <span class="kw1">namespace</span> views <span class="br0">{</span> <span class="kw1">inline</span> <span class="kw4">constexpr</span> <span class="coMULTI">/* unspecified */</span> reverse <span class="sy1">=</span> <span class="coMULTI">/* unspecified */</span><span class="sy4">;</span> <span class="br0">}</span>
 
  <span class="co1">// elements view</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span>input_range V, size_t N<span class="sy1">&gt;</span>
    requires <span class="coMULTI">/* see description */</span>
  <span class="kw1">class</span> elements_view<span class="sy4">;</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> T, size_t N<span class="sy1">&gt;</span>
    <span class="kw1">inline</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> enable_borrowed_range<span class="sy1">&lt;</span>elements_view<span class="sy1">&lt;</span>T, N<span class="sy1">&gt;&gt;</span> <span class="sy1">=</span>
      enable_borrowed_range<span class="sy1">&lt;</span>T<span class="sy1">&gt;</span><span class="sy4">;</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> R<span class="sy1">&gt;</span>
    <span class="kw1">using</span> keys_view <span class="sy1">=</span> elements_view<span class="sy1">&lt;</span>R, <span class="nu0">0</span><span class="sy1">&gt;</span><span class="sy4">;</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> R<span class="sy1">&gt;</span>
    <span class="kw1">using</span> values_view <span class="sy1">=</span> elements_view<span class="sy1">&lt;</span>R, <span class="nu0">1</span><span class="sy1">&gt;</span><span class="sy4">;</span>
 
  <span class="kw1">namespace</span> views <span class="br0">{</span>
    <span class="kw1">template</span><span class="sy1">&lt;</span>size_t N<span class="sy1">&gt;</span>
      <span class="kw1">inline</span> <span class="kw4">constexpr</span> <span class="coMULTI">/* unspecified */</span> elements <span class="sy1">=</span> <span class="coMULTI">/* unspecified */</span><span class="sy4">;</span>
    <span class="kw1">inline</span> <span class="kw4">constexpr</span> <span class="kw4">auto</span> keys <span class="sy1">=</span> elements<span class="sy1">&lt;</span><span class="nu0">0</span><span class="sy1">&gt;</span><span class="sy4">;</span>
    <span class="kw1">inline</span> <span class="kw4">constexpr</span> <span class="kw4">auto</span> values <span class="sy1">=</span> elements<span class="sy1">&lt;</span><span class="nu0">1</span><span class="sy1">&gt;</span><span class="sy4">;</span>
  <span class="br0">}</span>
 
  <span class="co1">// zip view</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span>input_range... <span class="me1">Views</span><span class="sy1">&gt;</span>
    requires <span class="br0">(</span>view<span class="sy1">&lt;</span>Views<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> ...<span class="br0">)</span> <span class="sy3">&amp;&amp;</span> <span class="br0">(</span>sizeof...<span class="br0">(</span>Views<span class="br0">)</span> <span class="sy1">&gt;</span> <span class="nu0">0</span><span class="br0">)</span>
  <span class="kw1">class</span> zip_view<span class="sy4">;</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span>... <span class="me1">Views</span><span class="sy1">&gt;</span>
    <span class="kw1">inline</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> enable_borrowed_range<span class="sy1">&lt;</span>zip_view<span class="sy1">&lt;</span>Views...<span class="sy1">&gt;&gt;</span> <span class="sy1">=</span>
      <span class="br0">(</span>enable_borrowed_range<span class="sy1">&lt;</span>Views<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> ...<span class="br0">)</span><span class="sy4">;</span>
 
  <span class="kw1">namespace</span> views <span class="br0">{</span> <span class="kw1">inline</span> <span class="kw4">constexpr</span> <span class="coMULTI">/* unspecified */</span> zip <span class="sy1">=</span> <span class="coMULTI">/* unspecified */</span><span class="sy4">;</span> <span class="br0">}</span>
 
  <span class="co1">// zip transform view</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span>copy_constructible F, input_range... <span class="me1">Views</span><span class="sy1">&gt;</span>
    requires <span class="br0">(</span>view<span class="sy1">&lt;</span>Views<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> ...<span class="br0">)</span> <span class="sy3">&amp;&amp;</span> <span class="br0">(</span>sizeof...<span class="br0">(</span>Views<span class="br0">)</span> <span class="sy1">&gt;</span> <span class="nu0">0</span><span class="br0">)</span> <span class="sy3">&amp;&amp;</span> is_object_v<span class="sy1">&lt;</span>F<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
             regular_invocable<span class="sy1">&lt;</span>F<span class="sy3">&amp;</span>, range_reference_t<span class="sy1">&lt;</span>Views<span class="sy1">&gt;</span>...<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
             <span class="coMULTI">/*can-reference*/</span><span class="sy1">&lt;</span>invoke_result_t<span class="sy1">&lt;</span>F<span class="sy3">&amp;</span>, range_reference_t<span class="sy1">&lt;</span>Views<span class="sy1">&gt;</span>...<span class="sy1">&gt;&gt;</span>
  <span class="kw1">class</span> zip_transform_view<span class="sy4">;</span>
 
  <span class="kw1">namespace</span> views <span class="br0">{</span>
    <span class="kw1">inline</span> <span class="kw4">constexpr</span> <span class="coMULTI">/* unspecified */</span> zip_transform <span class="sy1">=</span> <span class="coMULTI">/* unspecified */</span><span class="sy4">;</span> <span class="br0">}</span>
 
  <span class="co1">// adjacent view</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span>forward_range V, size_t N<span class="sy1">&gt;</span>
    requires view<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> <span class="br0">(</span>N <span class="sy1">&gt;</span> <span class="nu0">0</span><span class="br0">)</span>
  <span class="kw1">class</span> adjacent_view<span class="sy4">;</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> V, size_t N<span class="sy1">&gt;</span>
    <span class="kw1">inline</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> enable_borrowed_range<span class="sy1">&lt;</span>adjacent_view<span class="sy1">&lt;</span>V, N<span class="sy1">&gt;&gt;</span> <span class="sy1">=</span>
      enable_borrowed_range<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span><span class="sy4">;</span>
 
  <span class="kw1">namespace</span> views <span class="br0">{</span>
    <span class="kw1">template</span><span class="sy1">&lt;</span>size_t N<span class="sy1">&gt;</span>
      <span class="kw1">inline</span> <span class="kw4">constexpr</span> <span class="coMULTI">/* unspecified */</span> adjacent <span class="sy1">=</span> <span class="coMULTI">/* unspecified */</span> <span class="sy4">;</span>
    <span class="kw1">inline</span> <span class="kw4">constexpr</span> <span class="kw4">auto</span> pairwise <span class="sy1">=</span> adjacent<span class="sy1">&lt;</span><span class="nu0">2</span><span class="sy1">&gt;</span><span class="sy4">;</span>
  <span class="br0">}</span>
 
  <span class="co1">// adjacent transform view</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span>forward_range V, copy_constructible F, size_t N<span class="sy1">&gt;</span>
    requires <span class="coMULTI">/* see description */</span>
  <span class="kw1">class</span> adjacent_transform_view<span class="sy4">;</span>
 
  <span class="kw1">namespace</span> views <span class="br0">{</span>
    <span class="kw1">template</span><span class="sy1">&lt;</span>size_t N<span class="sy1">&gt;</span>
      <span class="kw1">inline</span> <span class="kw4">constexpr</span> <span class="coMULTI">/* unspecified */</span> adjacent_transform <span class="sy1">=</span> <span class="coMULTI">/* unspecified */</span><span class="sy4">;</span>
    <span class="kw1">inline</span> <span class="kw4">constexpr</span> <span class="kw4">auto</span> pairwise_transform <span class="sy1">=</span> adjacent_transform<span class="sy1">&lt;</span><span class="nu0">2</span><span class="sy1">&gt;</span><span class="sy4">;</span>
  <span class="br0">}</span>
 
  <span class="co1">// chunk view</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span>view V<span class="sy1">&gt;</span>
    requires input_range<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span>
  <span class="kw1">class</span> chunk_view<span class="sy4">;</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span>view V<span class="sy1">&gt;</span>
    requires forward_range<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span>
  <span class="kw1">class</span> chunk_view<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span><span class="sy4">;</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> V<span class="sy1">&gt;</span>
    <span class="kw1">inline</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> enable_borrowed_range<span class="sy1">&lt;</span>chunk_view<span class="sy1">&lt;</span>V<span class="sy1">&gt;&gt;</span> <span class="sy1">=</span>
      forward_range<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> enable_borrowed_range<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span><span class="sy4">;</span>
 
  <span class="kw1">namespace</span> views <span class="br0">{</span> <span class="kw1">inline</span> <span class="kw4">constexpr</span> <span class="coMULTI">/* unspecified */</span> chunk <span class="sy1">=</span> <span class="coMULTI">/* unspecified */</span><span class="sy4">;</span> <span class="br0">}</span>
 
  <span class="co1">// slide view</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span>view V<span class="sy1">&gt;</span>
    requires forward_range<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span>
  <span class="kw1">class</span> slide_view<span class="sy4">;</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> V<span class="sy1">&gt;</span>
    <span class="kw1">inline</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> enable_borrowed_range<span class="sy1">&lt;</span>slide_view<span class="sy1">&lt;</span>V<span class="sy1">&gt;&gt;</span> <span class="sy1">=</span>
      enable_borrowed_range<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span><span class="sy4">;</span>
 
  <span class="kw1">namespace</span> views <span class="br0">{</span> <span class="kw1">inline</span> <span class="kw4">constexpr</span> <span class="coMULTI">/* unspecified */</span> slide <span class="sy1">=</span> <span class="coMULTI">/* unspecified */</span><span class="sy4">;</span> <span class="br0">}</span>
 
  <span class="co1">// chunk by view</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span>forward_range V, indirect_binary_predicate<span class="sy1">&lt;</span>iterator_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span>, iterator_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;&gt;</span> Pred<span class="sy1">&gt;</span>
    requires view<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> is_object_v<span class="sy1">&lt;</span>Pred<span class="sy1">&gt;</span>
  <span class="kw1">class</span> chunk_by_view<span class="sy4">;</span>
 
  <span class="kw1">namespace</span> views <span class="br0">{</span> <span class="kw1">inline</span> <span class="kw4">constexpr</span> <span class="coMULTI">/* unspecified */</span> chunk_by <span class="sy1">=</span> <span class="coMULTI">/* unspecified */</span><span class="sy4">;</span> <span class="br0">}</span>
<span class="br0">}</span>
 
<span class="kw1">namespace</span> std <span class="br0">{</span>
  <span class="kw1">namespace</span> views <span class="sy1">=</span> ranges<span class="sy4">::</span><span class="me2">views</span><span class="sy4">;</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> T<span class="sy1">&gt;</span> <span class="kw1">struct</span> tuple_size<span class="sy4">;</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span>size_t I, <span class="kw1">class</span> T<span class="sy1">&gt;</span> <span class="kw1">struct</span> tuple_element<span class="sy4">;</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> I, <span class="kw1">class</span> S, ranges<span class="sy4">::</span><span class="me2">subrange_kind</span> K<span class="sy1">&gt;</span>
  <span class="kw1">struct</span> tuple_size<span class="sy1">&lt;</span><a href="../ranges/subrange.html"><span class="kw2913">ranges::<span class="me2">subrange</span></span></a><span class="sy1">&lt;</span>I, S, K<span class="sy1">&gt;&gt;</span>
    <span class="sy4">:</span> integral_constant<span class="sy1">&lt;</span>size_t, <span class="nu0">2</span><span class="sy1">&gt;</span> <span class="br0">{</span><span class="br0">}</span><span class="sy4">;</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> I, <span class="kw1">class</span> S, ranges<span class="sy4">::</span><span class="me2">subrange_kind</span> K<span class="sy1">&gt;</span>
  <span class="kw1">struct</span> tuple_element<span class="sy1">&lt;</span><span class="nu0">0</span>, <a href="../ranges/subrange.html"><span class="kw2913">ranges::<span class="me2">subrange</span></span></a><span class="sy1">&lt;</span>I, S, K<span class="sy1">&gt;&gt;</span> <span class="br0">{</span>
    <span class="kw1">using</span> type <span class="sy1">=</span> I<span class="sy4">;</span>
  <span class="br0">}</span><span class="sy4">;</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> I, <span class="kw1">class</span> S, ranges<span class="sy4">::</span><span class="me2">subrange_kind</span> K<span class="sy1">&gt;</span>
  <span class="kw1">struct</span> tuple_element<span class="sy1">&lt;</span><span class="nu0">1</span>, <a href="../ranges/subrange.html"><span class="kw2913">ranges::<span class="me2">subrange</span></span></a><span class="sy1">&lt;</span>I, S, K<span class="sy1">&gt;&gt;</span> <span class="br0">{</span>
    <span class="kw1">using</span> type <span class="sy1">=</span> S<span class="sy4">;</span>
  <span class="br0">}</span><span class="sy4">;</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> I, <span class="kw1">class</span> S, ranges<span class="sy4">::</span><span class="me2">subrange_kind</span> K<span class="sy1">&gt;</span>
  <span class="kw1">struct</span> tuple_element<span class="sy1">&lt;</span><span class="nu0">0</span>, <span class="kw4">const</span> <a href="../ranges/subrange.html"><span class="kw2913">ranges::<span class="me2">subrange</span></span></a><span class="sy1">&lt;</span>I, S, K<span class="sy1">&gt;&gt;</span> <span class="br0">{</span>
    <span class="kw1">using</span> type <span class="sy1">=</span> I<span class="sy4">;</span>
  <span class="br0">}</span><span class="sy4">;</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> I, <span class="kw1">class</span> S, ranges<span class="sy4">::</span><span class="me2">subrange_kind</span> K<span class="sy1">&gt;</span>
  <span class="kw1">struct</span> tuple_element<span class="sy1">&lt;</span><span class="nu0">1</span>, <span class="kw4">const</span> <a href="../ranges/subrange.html"><span class="kw2913">ranges::<span class="me2">subrange</span></span></a><span class="sy1">&lt;</span>I, S, K<span class="sy1">&gt;&gt;</span> <span class="br0">{</span>
    <span class="kw1">using</span> type <span class="sy1">=</span> S<span class="sy4">;</span>
  <span class="br0">}</span><span class="sy4">;</span>
 
  <span class="kw1">struct</span> from_range_t <span class="br0">{</span> <span class="kw1">explicit</span> from_range_t<span class="br0">(</span><span class="br0">)</span> <span class="sy1">=</span> <span class="kw1">default</span><span class="sy4">;</span> <span class="br0">}</span><span class="sy4">;</span>
  <span class="kw1">inline</span> <span class="kw4">constexpr</span> from_range_t from_range<span class="br0">{</span><span class="br0">}</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<h4><span class="mw-headline" id="Concept_range">Concept <a href="../ranges/range.html" title="cpp/ranges/range"><code>range</code></a></span></h4>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">namespace</span> std<span class="sy4">::</span><span class="me2">ranges</span> <span class="br0">{</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span> <span class="kw1">class</span> T <span class="sy1">&gt;</span>
    concept range <span class="sy1">=</span> requires<span class="br0">(</span>T<span class="sy3">&amp;</span> t<span class="br0">)</span> <span class="br0">{</span>
      <a href="../../../http:/en.cppreference.com/w/cpp/ranges-ranges-placeholder/begin"><span class="kw2885">ranges::<span class="me2">begin</span></span></a><span class="br0">(</span>t<span class="br0">)</span><span class="sy4">;</span> <span class="co1">// equality-preserving for forward iterators</span>
      <a href="../../../http:/en.cppreference.com/w/cpp/ranges-ranges-placeholder/end"><span class="kw2887">ranges::<span class="me2">end</span></span></a><span class="br0">(</span>t<span class="br0">)</span><span class="sy4">;</span>
  <span class="br0">}</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<h4><span class="mw-headline" id="Concept_borrowed_range">Concept <a href="../ranges/borrowed_range.html" title="cpp/ranges/borrowed range"><code>borrowed_range</code></a></span></h4>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">namespace</span> std<span class="sy4">::</span><span class="me2">ranges</span> <span class="br0">{</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> T<span class="sy1">&gt;</span>
    concept borrowed_range <span class="sy1">=</span>
      range<span class="sy1">&lt;</span>T<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> <span class="br0">(</span>is_lvalue_reference_v<span class="sy1">&lt;</span>T<span class="sy1">&gt;</span> <span class="sy3">||</span>
        enable_borrowed_range<span class="sy1">&lt;</span>remove_cvref_t<span class="sy1">&lt;</span>T<span class="sy1">&gt;&gt;</span><span class="br0">)</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<h4><span class="mw-headline" id="Concept_sized_range">Concept <a href="../ranges/sized_range.html" title="cpp/ranges/sized range"><code>sized_range</code></a></span></h4>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">namespace</span> std<span class="sy4">::</span><span class="me2">ranges</span> <span class="br0">{</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span> <span class="kw1">class</span> T <span class="sy1">&gt;</span>
    concept sized_range <span class="sy1">=</span> range<span class="sy1">&lt;</span>T<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
      requires<span class="br0">(</span>T<span class="sy3">&amp;</span> t<span class="br0">)</span> <span class="br0">{</span>
        <a href="../ranges/size.html"><span class="kw3103">ranges::<span class="me2">size</span></span></a><span class="br0">(</span>t<span class="br0">)</span><span class="sy4">;</span>
      <span class="br0">}</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<h4><span class="mw-headline" id="Concept_view">Concept <a href="../ranges/view.html" title="cpp/ranges/view"><code>view</code></a></span></h4>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">namespace</span> std<span class="sy4">::</span><span class="me2">ranges</span> <span class="br0">{</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> T<span class="sy1">&gt;</span>
    <span class="kw1">inline</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> enable_view <span class="sy1">=</span> derived_from<span class="sy1">&lt;</span>T, view_base<span class="sy1">&gt;</span><span class="sy4">;</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> T<span class="sy1">&gt;</span>
    concept view <span class="sy1">=</span> range<span class="sy1">&lt;</span>T<span class="sy1">&gt;</span>
                <span class="sy3">&amp;&amp;</span> movable<span class="sy1">&lt;</span>T<span class="sy1">&gt;</span>
                <span class="sy3">&amp;&amp;</span> enable_view<span class="sy1">&lt;</span>T<span class="sy1">&gt;</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<h4><span class="mw-headline" id="Concept_output_range">Concept <a href="../ranges/output_range.html" title="cpp/ranges/output range"><code>output_range</code></a></span></h4>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">namespace</span> std<span class="sy4">::</span><span class="me2">ranges</span> <span class="br0">{</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> R, <span class="kw1">class</span> T<span class="sy1">&gt;</span>
    concept output_range <span class="sy1">=</span>
      range<span class="sy1">&lt;</span>R<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> output_iterator<span class="sy1">&lt;</span>iterator_t<span class="sy1">&lt;</span>R<span class="sy1">&gt;</span>, T<span class="sy1">&gt;</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<h4><span class="mw-headline" id="Concept_input_range">Concept <a href="../ranges/input_range.html" title="cpp/ranges/input range"><code>input_range</code></a></span></h4>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">namespace</span> std<span class="sy4">::</span><span class="me2">ranges</span> <span class="br0">{</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> T<span class="sy1">&gt;</span>
    concept input_range <span class="sy1">=</span>
      range<span class="sy1">&lt;</span>T<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> input_iterator<span class="sy1">&lt;</span>iterator_t<span class="sy1">&lt;</span>T<span class="sy1">&gt;&gt;</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<h4><span class="mw-headline" id="Concept_forward_range">Concept <a href="../ranges/forward_range.html" title="cpp/ranges/forward range"><code>forward_range</code></a></span></h4>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">namespace</span> std<span class="sy4">::</span><span class="me2">ranges</span> <span class="br0">{</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> T<span class="sy1">&gt;</span>
    concept forward_range <span class="sy1">=</span>
      input_range<span class="sy1">&lt;</span>T<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> forward_iterator<span class="sy1">&lt;</span>iterator_t<span class="sy1">&lt;</span>T<span class="sy1">&gt;&gt;</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<h4><span class="mw-headline" id="Concept_bidirectional_range">Concept <a href="../ranges/bidirectional_range.html" title="cpp/ranges/bidirectional range"><code>bidirectional_range</code></a></span></h4>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">namespace</span> std<span class="sy4">::</span><span class="me2">ranges</span> <span class="br0">{</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> T<span class="sy1">&gt;</span>
    concept bidirectional_range <span class="sy1">=</span>
      forward_range<span class="sy1">&lt;</span>T<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> bidirectional_iterator<span class="sy1">&lt;</span>iterator_t<span class="sy1">&lt;</span>T<span class="sy1">&gt;&gt;</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<h4><span class="mw-headline" id="Concept_random_access_range">Concept <a href="../ranges/random_access_range.html" title="cpp/ranges/random access range"><code>random_access_range</code></a></span></h4>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">namespace</span> std<span class="sy4">::</span><span class="me2">ranges</span> <span class="br0">{</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> T<span class="sy1">&gt;</span>
    concept random_access_range <span class="sy1">=</span>
      bidirectional_range<span class="sy1">&lt;</span>T<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> random_access_iterator<span class="sy1">&lt;</span>iterator_t<span class="sy1">&lt;</span>T<span class="sy1">&gt;&gt;</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<h4><span class="mw-headline" id="Concept_contiguous_range">Concept <a href="../ranges/contiguous_range.html" title="cpp/ranges/contiguous range"><code>contiguous_range</code></a></span></h4>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">namespace</span> std<span class="sy4">::</span><span class="me2">ranges</span> <span class="br0">{</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> T<span class="sy1">&gt;</span>
    concept contiguous_range <span class="sy1">=</span>
      random_access_range<span class="sy1">&lt;</span>T<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> contiguous_iterator<span class="sy1">&lt;</span>iterator_t<span class="sy1">&lt;</span>T<span class="sy1">&gt;&gt;</span> <span class="sy3">&amp;&amp;</span>
        requires<span class="br0">(</span>T<span class="sy3">&amp;</span> t<span class="br0">)</span> <span class="br0">{</span>
          <span class="br0">{</span> <a href="../../../http:/en.cppreference.com/w/cpp/ranges-ranges-placeholder/data"><span class="kw2891">ranges::<span class="me2">data</span></span></a><span class="br0">(</span>t<span class="br0">)</span> <span class="br0">}</span> <span class="sy2">-</span><span class="sy1">&gt;</span> same_as<span class="sy1">&lt;</span>add_pointer_t<span class="sy1">&lt;</span>range_reference_t<span class="sy1">&lt;</span>T<span class="sy1">&gt;&gt;&gt;</span><span class="sy4">;</span>
        <span class="br0">}</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<h4><span class="mw-headline" id="Concept_common_range">Concept <a href="../ranges/common_range.html" title="cpp/ranges/common range"><code>common_range</code></a></span></h4>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">namespace</span> std<span class="sy4">::</span><span class="me2">ranges</span> <span class="br0">{</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> T<span class="sy1">&gt;</span>
    concept common_range <span class="sy1">=</span>
      range<span class="sy1">&lt;</span>T<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> same_as<span class="sy1">&lt;</span>iterator_t<span class="sy1">&lt;</span>T<span class="sy1">&gt;</span>, sentinel_t<span class="sy1">&lt;</span>T<span class="sy1">&gt;&gt;</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<h4><span class="mw-headline" id="Concept_viewable_range">Concept <a href="../ranges/viewable_range.html" title="cpp/ranges/viewable range"><code>viewable_range</code></a></span></h4>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">namespace</span> std<span class="sy4">::</span><span class="me2">ranges</span> <span class="br0">{</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> T<span class="sy1">&gt;</span>
    concept viewable_range <span class="sy1">=</span>
      range<span class="sy1">&lt;</span>T<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> <span class="br0">(</span>borrowed_range<span class="sy1">&lt;</span>T<span class="sy1">&gt;</span> <span class="sy3">||</span> view<span class="sy1">&lt;</span>remove_cvref_t<span class="sy1">&lt;</span>T<span class="sy1">&gt;&gt;</span><span class="br0">)</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<h4><span class="mw-headline" id="Helper_concepts">Helper concepts</span></h4>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">namespace</span> std<span class="sy4">::</span><span class="me2">ranges</span> <span class="br0">{</span> <span class="co1">// unspecified, for name lookup only</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> R<span class="sy1">&gt;</span>
    concept <span class="coMULTI">/*simple-view*/</span> <span class="sy1">=</span>                                     <span class="co1">// exposition only</span>
      view<span class="sy1">&lt;</span>R<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> range<span class="sy1">&lt;</span><span class="kw4">const</span> R<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
      same_as<span class="sy1">&lt;</span>iterator_t<span class="sy1">&lt;</span>R<span class="sy1">&gt;</span>, iterator_t<span class="sy1">&lt;</span><span class="kw4">const</span> R<span class="sy1">&gt;&gt;</span> <span class="sy3">&amp;&amp;</span>
      same_as<span class="sy1">&lt;</span>sentinel_t<span class="sy1">&lt;</span>R<span class="sy1">&gt;</span>, sentinel_t<span class="sy1">&lt;</span><span class="kw4">const</span> R<span class="sy1">&gt;&gt;</span><span class="sy4">;</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> I<span class="sy1">&gt;</span>
    concept <span class="coMULTI">/*has-arrow*/</span> <span class="sy1">=</span>                                       <span class="co1">// exposition only</span>
      input_iterator<span class="sy1">&lt;</span>I<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
      <span class="br0">(</span>is_pointer_v<span class="sy1">&lt;</span>I<span class="sy1">&gt;</span> <span class="sy3">||</span> requires<span class="br0">(</span>I i<span class="br0">)</span> <span class="br0">{</span> i.<span class="me1">operator</span><span class="sy2">-</span><span class="sy1">&gt;</span><span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span> <span class="br0">}</span><span class="br0">)</span><span class="sy4">;</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> T, <span class="kw1">class</span> U<span class="sy1">&gt;</span>
    concept <span class="coMULTI">/*different-from*/</span> <span class="sy1">=</span>                                  <span class="co1">// exposition only</span>
      <span class="sy3">!</span>same_as<span class="sy1">&lt;</span>remove_cvref_t<span class="sy1">&lt;</span>T<span class="sy1">&gt;</span>, remove_cvref_t<span class="sy1">&lt;</span>U<span class="sy1">&gt;&gt;</span><span class="sy4">;</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> I<span class="sy1">&gt;</span>
    concept <span class="coMULTI">/*decrementable*/</span> <span class="sy1">=</span>                                   <span class="co1">// exposition only</span>
      incrementable<span class="sy1">&lt;</span>I<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> requires<span class="br0">(</span>I i<span class="br0">)</span> <span class="br0">{</span>
        <span class="br0">{</span> <span class="sy2">--</span>i <span class="br0">}</span> <span class="sy2">-</span><span class="sy1">&gt;</span> same_as<span class="sy1">&lt;</span>I<span class="sy3">&amp;</span><span class="sy1">&gt;</span><span class="sy4">;</span>
        <span class="br0">{</span> i<span class="sy2">--</span> <span class="br0">}</span> <span class="sy2">-</span><span class="sy1">&gt;</span> same_as<span class="sy1">&lt;</span>I<span class="sy1">&gt;</span><span class="sy4">;</span>
      <span class="br0">}</span><span class="sy4">;</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> I<span class="sy1">&gt;</span>
    concept <span class="coMULTI">/*advanceable*/</span> <span class="sy1">=</span>                                     <span class="co1">// exposition only</span>
      <span class="coMULTI">/*decrementable*/</span><span class="sy1">&lt;</span>I<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> totally_ordered<span class="sy1">&lt;</span>I<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
      requires<span class="br0">(</span>I i, <span class="kw4">const</span> I j, <span class="kw4">const</span> iter_difference_t<span class="sy1">&lt;</span>I<span class="sy1">&gt;</span> n<span class="br0">)</span> <span class="br0">{</span>
          <span class="br0">{</span> i <span class="sy2">+</span><span class="sy1">=</span> n <span class="br0">}</span> <span class="sy2">-</span><span class="sy1">&gt;</span> same_as<span class="sy1">&lt;</span>I<span class="sy3">&amp;</span><span class="sy1">&gt;</span><span class="sy4">;</span>
          <span class="br0">{</span> i <span class="sy2">-</span><span class="sy1">=</span> n <span class="br0">}</span> <span class="sy2">-</span><span class="sy1">&gt;</span> same_as<span class="sy1">&lt;</span>I<span class="sy3">&amp;</span><span class="sy1">&gt;</span><span class="sy4">;</span>
        I <span class="br0">{</span> j <span class="sy2">+</span>  n <span class="br0">}</span><span class="sy4">;</span>
        I <span class="br0">{</span> n <span class="sy2">+</span>  j <span class="br0">}</span><span class="sy4">;</span>
        I <span class="br0">{</span> j <span class="sy2">-</span>  n <span class="br0">}</span><span class="sy4">;</span>
          <span class="br0">{</span> j <span class="sy2">-</span>  j <span class="br0">}</span> <span class="sy2">-</span><span class="sy1">&gt;</span> convertible_to<span class="sy1">&lt;</span>iter_difference_t<span class="sy1">&lt;</span>I<span class="sy1">&gt;&gt;</span><span class="sy4">;</span>
      <span class="br0">}</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<p>Note: These names are only for exposition, they are not part of the interface.
</p>
<h4><span class="mw-headline" id="Class_template_std::ranges::view_interface">Class template <span class="t-lc">std::ranges::view_interface</span></span></h4>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">namespace</span> std<span class="sy4">::</span><span class="me2">ranges</span> <span class="br0">{</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> D<span class="sy1">&gt;</span>
    requires is_class_v<span class="sy1">&lt;</span>D<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> same_as<span class="sy1">&lt;</span>D, remove_cv_t<span class="sy1">&lt;</span>D<span class="sy1">&gt;&gt;</span>
  <span class="kw1">class</span> view_interface <span class="br0">{</span>
  <span class="kw1">private</span><span class="sy4">:</span>
    <span class="kw4">constexpr</span> D<span class="sy3">&amp;</span> derived<span class="br0">(</span><span class="br0">)</span> <span class="kw1">noexcept</span> <span class="br0">{</span>               <span class="co1">// exposition only</span>
      <span class="kw1">return</span> <span class="kw1">static_cast</span><span class="sy1">&lt;</span>D<span class="sy3">&amp;</span><span class="sy1">&gt;</span><span class="br0">(</span><span class="sy2">*</span>this<span class="br0">)</span><span class="sy4">;</span>
    <span class="br0">}</span>
    <span class="kw4">constexpr</span> <span class="kw4">const</span> D<span class="sy3">&amp;</span> derived<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span> <span class="kw1">noexcept</span> <span class="br0">{</span>   <span class="co1">// exposition only</span>
      <span class="kw1">return</span> <span class="kw1">static_cast</span><span class="sy1">&lt;</span><span class="kw4">const</span> D<span class="sy3">&amp;</span><span class="sy1">&gt;</span><span class="br0">(</span><span class="sy2">*</span>this<span class="br0">)</span><span class="sy4">;</span>
    <span class="br0">}</span>
 
  <span class="kw1">public</span><span class="sy4">:</span>
    <span class="kw4">constexpr</span> <span class="kw4">bool</span> empty<span class="br0">(</span><span class="br0">)</span> requires forward_range<span class="sy1">&lt;</span>D<span class="sy1">&gt;</span> <span class="br0">{</span>
      <span class="kw1">return</span> <a href="../../../http:/en.cppreference.com/w/cpp/ranges-ranges-placeholder/begin"><span class="kw2885">ranges::<span class="me2">begin</span></span></a><span class="br0">(</span>derived<span class="br0">(</span><span class="br0">)</span><span class="br0">)</span> <span class="sy1">==</span> <a href="../../../http:/en.cppreference.com/w/cpp/ranges-ranges-placeholder/end"><span class="kw2887">ranges::<span class="me2">end</span></span></a><span class="br0">(</span>derived<span class="br0">(</span><span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
    <span class="br0">}</span>
    <span class="kw4">constexpr</span> <span class="kw4">bool</span> empty<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span> requires forward_range<span class="sy1">&lt;</span><span class="kw4">const</span> D<span class="sy1">&gt;</span> <span class="br0">{</span>
      <span class="kw1">return</span> <a href="../../../http:/en.cppreference.com/w/cpp/ranges-ranges-placeholder/begin"><span class="kw2885">ranges::<span class="me2">begin</span></span></a><span class="br0">(</span>derived<span class="br0">(</span><span class="br0">)</span><span class="br0">)</span> <span class="sy1">==</span> <a href="../../../http:/en.cppreference.com/w/cpp/ranges-ranges-placeholder/end"><span class="kw2887">ranges::<span class="me2">end</span></span></a><span class="br0">(</span>derived<span class="br0">(</span><span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
    <span class="br0">}</span>
 
    <span class="kw4">constexpr</span> <span class="kw1">explicit</span> operator <span class="kw4">bool</span><span class="br0">(</span><span class="br0">)</span>
      requires requires <span class="br0">{</span> <a href="../ranges/empty.html"><span class="kw3105">ranges::<span class="me2">empty</span></span></a><span class="br0">(</span>derived<span class="br0">(</span><span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span> <span class="br0">}</span> <span class="br0">{</span>
        <span class="kw1">return</span> <span class="sy3">!</span><a href="../ranges/empty.html"><span class="kw3105">ranges::<span class="me2">empty</span></span></a><span class="br0">(</span>derived<span class="br0">(</span><span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
      <span class="br0">}</span>
    <span class="kw4">constexpr</span> <span class="kw1">explicit</span> operator <span class="kw4">bool</span><span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span>
      requires requires <span class="br0">{</span> <a href="../ranges/empty.html"><span class="kw3105">ranges::<span class="me2">empty</span></span></a><span class="br0">(</span>derived<span class="br0">(</span><span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span> <span class="br0">}</span> <span class="br0">{</span>
        <span class="kw1">return</span> <span class="sy3">!</span><a href="../ranges/empty.html"><span class="kw3105">ranges::<span class="me2">empty</span></span></a><span class="br0">(</span>derived<span class="br0">(</span><span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
      <span class="br0">}</span>
 
    <span class="kw4">constexpr</span> <span class="kw4">auto</span> data<span class="br0">(</span><span class="br0">)</span> requires contiguous_iterator<span class="sy1">&lt;</span>iterator_t<span class="sy1">&lt;</span>D<span class="sy1">&gt;&gt;</span> <span class="br0">{</span>
      <span class="kw1">return</span> to_address<span class="br0">(</span><a href="../../../http:/en.cppreference.com/w/cpp/ranges-ranges-placeholder/begin"><span class="kw2885">ranges::<span class="me2">begin</span></span></a><span class="br0">(</span>derived<span class="br0">(</span><span class="br0">)</span><span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
    <span class="br0">}</span>
    <span class="kw4">constexpr</span> <span class="kw4">auto</span> data<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span>
      requires range<span class="sy1">&lt;</span><span class="kw4">const</span> D<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> contiguous_iterator<span class="sy1">&lt;</span>iterator_t<span class="sy1">&lt;</span><span class="kw4">const</span> D<span class="sy1">&gt;&gt;</span> <span class="br0">{</span>
        <span class="kw1">return</span> to_address<span class="br0">(</span><a href="../../../http:/en.cppreference.com/w/cpp/ranges-ranges-placeholder/begin"><span class="kw2885">ranges::<span class="me2">begin</span></span></a><span class="br0">(</span>derived<span class="br0">(</span><span class="br0">)</span><span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
      <span class="br0">}</span>
 
    <span class="kw4">constexpr</span> <span class="kw4">auto</span> size<span class="br0">(</span><span class="br0">)</span> requires forward_range<span class="sy1">&lt;</span>D<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
      sized_sentinel_for<span class="sy1">&lt;</span>sentinel_t<span class="sy1">&lt;</span>D<span class="sy1">&gt;</span>, iterator_t<span class="sy1">&lt;</span>D<span class="sy1">&gt;&gt;</span> <span class="br0">{</span>
        <span class="kw1">return</span> <a href="../../../http:/en.cppreference.com/w/cpp/ranges-ranges-placeholder/end"><span class="kw2887">ranges::<span class="me2">end</span></span></a><span class="br0">(</span>derived<span class="br0">(</span><span class="br0">)</span><span class="br0">)</span> <span class="sy2">-</span> <a href="../../../http:/en.cppreference.com/w/cpp/ranges-ranges-placeholder/begin"><span class="kw2885">ranges::<span class="me2">begin</span></span></a><span class="br0">(</span>derived<span class="br0">(</span><span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
      <span class="br0">}</span>
    <span class="kw4">constexpr</span> <span class="kw4">auto</span> size<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span> requires forward_range<span class="sy1">&lt;</span><span class="kw4">const</span> D<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
      sized_sentinel_for<span class="sy1">&lt;</span>sentinel_t<span class="sy1">&lt;</span><span class="kw4">const</span> D<span class="sy1">&gt;</span>, iterator_t<span class="sy1">&lt;</span><span class="kw4">const</span> D<span class="sy1">&gt;&gt;</span> <span class="br0">{</span>
        <span class="kw1">return</span> <a href="../../../http:/en.cppreference.com/w/cpp/ranges-ranges-placeholder/end"><span class="kw2887">ranges::<span class="me2">end</span></span></a><span class="br0">(</span>derived<span class="br0">(</span><span class="br0">)</span><span class="br0">)</span> <span class="sy2">-</span> <a href="../../../http:/en.cppreference.com/w/cpp/ranges-ranges-placeholder/begin"><span class="kw2885">ranges::<span class="me2">begin</span></span></a><span class="br0">(</span>derived<span class="br0">(</span><span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
      <span class="br0">}</span>
 
    <span class="kw4">constexpr</span> decltype<span class="br0">(</span><span class="kw4">auto</span><span class="br0">)</span> front<span class="br0">(</span><span class="br0">)</span> requires forward_range<span class="sy1">&lt;</span>D<span class="sy1">&gt;</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> decltype<span class="br0">(</span><span class="kw4">auto</span><span class="br0">)</span> front<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span> requires forward_range<span class="sy1">&lt;</span><span class="kw4">const</span> D<span class="sy1">&gt;</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> decltype<span class="br0">(</span><span class="kw4">auto</span><span class="br0">)</span> back<span class="br0">(</span><span class="br0">)</span> requires bidirectional_range<span class="sy1">&lt;</span>D<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> common_range<span class="sy1">&lt;</span>D<span class="sy1">&gt;</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> decltype<span class="br0">(</span><span class="kw4">auto</span><span class="br0">)</span> back<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span>
      requires bidirectional_range<span class="sy1">&lt;</span><span class="kw4">const</span> D<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> common_range<span class="sy1">&lt;</span><span class="kw4">const</span> D<span class="sy1">&gt;</span><span class="sy4">;</span>
 
    <span class="kw1">template</span><span class="sy1">&lt;</span>random_access_range R <span class="sy1">=</span> D<span class="sy1">&gt;</span>
      <span class="kw4">constexpr</span> decltype<span class="br0">(</span><span class="kw4">auto</span><span class="br0">)</span> operator<span class="br0">[</span><span class="br0">]</span><span class="br0">(</span>range_difference_t<span class="sy1">&lt;</span>R<span class="sy1">&gt;</span> n<span class="br0">)</span> <span class="br0">{</span>
        <span class="kw1">return</span> <a href="../../../http:/en.cppreference.com/w/cpp/ranges-ranges-placeholder/begin"><span class="kw2885">ranges::<span class="me2">begin</span></span></a><span class="br0">(</span>derived<span class="br0">(</span><span class="br0">)</span><span class="br0">)</span><span class="br0">[</span>n<span class="br0">]</span><span class="sy4">;</span>
      <span class="br0">}</span>
    <span class="kw1">template</span><span class="sy1">&lt;</span>random_access_range R <span class="sy1">=</span> <span class="kw4">const</span> D<span class="sy1">&gt;</span>
      <span class="kw4">constexpr</span> decltype<span class="br0">(</span><span class="kw4">auto</span><span class="br0">)</span> operator<span class="br0">[</span><span class="br0">]</span><span class="br0">(</span>range_difference_t<span class="sy1">&lt;</span>R<span class="sy1">&gt;</span> n<span class="br0">)</span> <span class="kw4">const</span> <span class="br0">{</span>
        <span class="kw1">return</span> <a href="../../../http:/en.cppreference.com/w/cpp/ranges-ranges-placeholder/begin"><span class="kw2885">ranges::<span class="me2">begin</span></span></a><span class="br0">(</span>derived<span class="br0">(</span><span class="br0">)</span><span class="br0">)</span><span class="br0">[</span>n<span class="br0">]</span><span class="sy4">;</span>
      <span class="br0">}</span>
  <span class="br0">}</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<h4><span class="mw-headline" id="Class_template_std::ranges::subrange">Class template <span class="t-lc"><a href="../ranges/subrange.html" title="cpp/ranges/subrange">std::ranges::subrange</a></span></span></h4>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">namespace</span> std<span class="sy4">::</span><span class="me2">ranges</span> <span class="br0">{</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> From, <span class="kw1">class</span> To<span class="sy1">&gt;</span>
    concept <span class="coMULTI">/*uses-nonqualification-pointer-conversion*/</span> <span class="sy1">=</span>      <span class="co1">// exposition only</span>
      is_pointer_v<span class="sy1">&lt;</span>From<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> is_pointer_v<span class="sy1">&lt;</span>To<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
      <span class="sy3">!</span>convertible_to<span class="sy1">&lt;</span>remove_pointer_t<span class="sy1">&lt;</span>From<span class="sy1">&gt;</span><span class="br0">(</span><span class="sy2">*</span><span class="br0">)</span><span class="br0">[</span><span class="br0">]</span>, remove_pointer_t<span class="sy1">&lt;</span>To<span class="sy1">&gt;</span><span class="br0">(</span><span class="sy2">*</span><span class="br0">)</span><span class="br0">[</span><span class="br0">]</span><span class="sy1">&gt;</span><span class="sy4">;</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> From, <span class="kw1">class</span> To<span class="sy1">&gt;</span>
    concept <span class="coMULTI">/*convertible-to-non-slicing*/</span> <span class="sy1">=</span>                    <span class="co1">// exposition only</span>
      convertible_to<span class="sy1">&lt;</span>From, To<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
      <span class="sy3">!</span><span class="coMULTI">/*uses-nonqualification-pointer-conversion*/</span><span class="sy1">&lt;</span>decay_t<span class="sy1">&lt;</span>From<span class="sy1">&gt;</span>, decay_t<span class="sy1">&lt;</span>To<span class="sy1">&gt;&gt;</span><span class="sy4">;</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> T<span class="sy1">&gt;</span>
    concept <span class="coMULTI">/*pair-like*/</span> <span class="sy1">=</span>                                     <span class="co1">// exposition only</span>
      <span class="sy3">!</span>is_reference_v<span class="sy1">&lt;</span>T<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> requires<span class="br0">(</span>T t<span class="br0">)</span> <span class="br0">{</span>
        <span class="kw1">typename</span> tuple_size<span class="sy1">&lt;</span>T<span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">type</span><span class="sy4">;</span>                       <span class="co1">// ensures tuple_size&lt;T&gt;</span>
                                                            <span class="co1">// is complete</span>
        requires derived_from<span class="sy1">&lt;</span>tuple_size<span class="sy1">&lt;</span>T<span class="sy1">&gt;</span>, integral_constant<span class="sy1">&lt;</span>size_t, <span class="nu0">2</span><span class="sy1">&gt;&gt;</span><span class="sy4">;</span>
        <span class="kw1">typename</span> tuple_element_t<span class="sy1">&lt;</span><span class="nu0">0</span>, remove_const_t<span class="sy1">&lt;</span>T<span class="sy1">&gt;&gt;</span><span class="sy4">;</span>
        <span class="kw1">typename</span> tuple_element_t<span class="sy1">&lt;</span><span class="nu0">1</span>, remove_const_t<span class="sy1">&lt;</span>T<span class="sy1">&gt;&gt;</span><span class="sy4">;</span>
        <span class="br0">{</span> <a href="../utility/variant/get.html"><span class="kw3220">std::<span class="me2">get</span></span></a><span class="sy1">&lt;</span><span class="nu0">0</span><span class="sy1">&gt;</span><span class="br0">(</span>t<span class="br0">)</span> <span class="br0">}</span> <span class="sy2">-</span><span class="sy1">&gt;</span> convertible_to<span class="sy1">&lt;</span><span class="kw4">const</span> tuple_element_t<span class="sy1">&lt;</span><span class="nu0">0</span>, T<span class="sy1">&gt;</span><span class="sy3">&amp;</span><span class="sy1">&gt;</span><span class="sy4">;</span>
        <span class="br0">{</span> <a href="../utility/variant/get.html"><span class="kw3220">std::<span class="me2">get</span></span></a><span class="sy1">&lt;</span><span class="nu0">1</span><span class="sy1">&gt;</span><span class="br0">(</span>t<span class="br0">)</span> <span class="br0">}</span> <span class="sy2">-</span><span class="sy1">&gt;</span> convertible_to<span class="sy1">&lt;</span><span class="kw4">const</span> tuple_element_t<span class="sy1">&lt;</span><span class="nu0">1</span>, T<span class="sy1">&gt;</span><span class="sy3">&amp;</span><span class="sy1">&gt;</span><span class="sy4">;</span>
      <span class="br0">}</span><span class="sy4">;</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> T, <span class="kw1">class</span> U, <span class="kw1">class</span> V<span class="sy1">&gt;</span>
    concept <span class="coMULTI">/*pair-like-convertible-from*/</span> <span class="sy1">=</span>                    <span class="co1">// exposition only</span>
      <span class="sy3">!</span>range<span class="sy1">&lt;</span>T<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> <span class="coMULTI">/*pair-like*/</span><span class="sy1">&lt;</span>T<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
      constructible_from<span class="sy1">&lt;</span>T, U, V<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
      <span class="coMULTI">/*convertible-to-non-slicing*/</span><span class="sy1">&lt;</span>U, tuple_element_t<span class="sy1">&lt;</span><span class="nu0">0</span>, T<span class="sy1">&gt;&gt;</span> <span class="sy3">&amp;&amp;</span>
      convertible_to<span class="sy1">&lt;</span>V, tuple_element_t<span class="sy1">&lt;</span><span class="nu0">1</span>, T<span class="sy1">&gt;&gt;</span><span class="sy4">;</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span>input_or_output_iterator I, sentinel_for<span class="sy1">&lt;</span>I<span class="sy1">&gt;</span> S <span class="sy1">=</span> I, subrange_kind K <span class="sy1">=</span>
      sized_sentinel_for<span class="sy1">&lt;</span>S, I<span class="sy1">&gt;</span> <span class="sy4">?</span> subrange_kind<span class="sy4">::</span><span class="me2">sized</span> <span class="sy4">:</span> subrange_kind<span class="sy4">::</span><span class="me2">unsized</span><span class="sy1">&gt;</span>
    requires <span class="br0">(</span>K <span class="sy1">==</span> subrange_kind<span class="sy4">::</span><span class="me2">sized</span> <span class="sy3">||</span> <span class="sy3">!</span>sized_sentinel_for<span class="sy1">&lt;</span>S, I<span class="sy1">&gt;</span><span class="br0">)</span>
  <span class="kw1">class</span> subrange <span class="sy4">:</span> <span class="kw1">public</span> view_interface<span class="sy1">&lt;</span>subrange<span class="sy1">&lt;</span>I, S, K<span class="sy1">&gt;&gt;</span> <span class="br0">{</span>
  <span class="kw1">private</span><span class="sy4">:</span>
    <span class="kw4">static</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> StoreSize <span class="sy1">=</span>                       <span class="co1">// exposition only</span>
      K <span class="sy1">==</span> subrange_kind<span class="sy4">::</span><span class="me2">sized</span> <span class="sy3">&amp;&amp;</span> <span class="sy3">!</span>sized_sentinel_for<span class="sy1">&lt;</span>S, I<span class="sy1">&gt;</span><span class="sy4">;</span>
    I begin_ <span class="sy1">=</span> I<span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>                                         <span class="co1">// exposition only</span>
    S end_ <span class="sy1">=</span> S<span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>                                           <span class="co1">// exposition only</span>
    <span class="coMULTI">/*make-unsigned-like-t*/</span><span class="sy1">&lt;</span>iter_difference_t<span class="sy1">&lt;</span>I<span class="sy1">&gt;&gt;</span> size_ <span class="sy1">=</span> <span class="nu0">0</span><span class="sy4">;</span>   <span class="co1">// exposition only;</span>
                                                                <span class="co1">// present only</span>
                                                                <span class="co1">// when StoreSize is true</span>
  <span class="kw1">public</span><span class="sy4">:</span>
    subrange<span class="br0">(</span><span class="br0">)</span> requires default_initializable<span class="sy1">&lt;</span>I<span class="sy1">&gt;</span> <span class="sy1">=</span> <span class="kw1">default</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> subrange<span class="br0">(</span><span class="coMULTI">/*convertible-to-non-slicing*/</span><span class="sy1">&lt;</span>I<span class="sy1">&gt;</span> <span class="kw4">auto</span> i, S s<span class="br0">)</span>
      requires <span class="br0">(</span><span class="sy3">!</span>StoreSize<span class="br0">)</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> subrange<span class="br0">(</span><span class="coMULTI">/*convertible-to-non-slicing*/</span><span class="sy1">&lt;</span>I<span class="sy1">&gt;</span> <span class="kw4">auto</span> i, S s,
                       <span class="coMULTI">/*make-unsigned-like-t*/</span><span class="sy1">&lt;</span>iter_difference_t<span class="sy1">&lt;</span>I<span class="sy1">&gt;&gt;</span> n<span class="br0">)</span>
      requires <span class="br0">(</span>K <span class="sy1">==</span> subrange_kind<span class="sy4">::</span><span class="me2">sized</span><span class="br0">)</span><span class="sy4">;</span>
 
    <span class="kw1">template</span><span class="sy1">&lt;</span><span class="coMULTI">/*different-from*/</span><span class="sy1">&lt;</span>subrange<span class="sy1">&gt;</span> R<span class="sy1">&gt;</span>
      requires borrowed_range<span class="sy1">&lt;</span>R<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
               <span class="coMULTI">/*convertible-to-non-slicing*/</span><span class="sy1">&lt;</span>iterator_t<span class="sy1">&lt;</span>R<span class="sy1">&gt;</span>, I<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
               convertible_to<span class="sy1">&lt;</span>sentinel_t<span class="sy1">&lt;</span>R<span class="sy1">&gt;</span>, S<span class="sy1">&gt;</span>
    <span class="kw4">constexpr</span> subrange<span class="br0">(</span>R<span class="sy3">&amp;&amp;</span> r<span class="br0">)</span> requires <span class="br0">(</span><span class="sy3">!</span>StoreSize <span class="sy3">||</span> sized_range<span class="sy1">&lt;</span>R<span class="sy1">&gt;</span><span class="br0">)</span><span class="sy4">;</span>
 
    <span class="kw1">template</span><span class="sy1">&lt;</span>borrowed_range R<span class="sy1">&gt;</span>
      requires <span class="coMULTI">/*convertible-to-non-slicing*/</span><span class="sy1">&lt;</span>iterator_t<span class="sy1">&lt;</span>R<span class="sy1">&gt;</span>, I<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
               convertible_to<span class="sy1">&lt;</span>sentinel_t<span class="sy1">&lt;</span>R<span class="sy1">&gt;</span>, S<span class="sy1">&gt;</span>
    <span class="kw4">constexpr</span> subrange<span class="br0">(</span>R<span class="sy3">&amp;&amp;</span> r, <span class="coMULTI">/*make-unsigned-like-t*/</span><span class="sy1">&lt;</span>iter_difference_t<span class="sy1">&lt;</span>I<span class="sy1">&gt;&gt;</span> n<span class="br0">)</span>
      requires <span class="br0">(</span>K <span class="sy1">==</span> subrange_kind<span class="sy4">::</span><span class="me2">sized</span><span class="br0">)</span>
        <span class="sy4">:</span> subrange<span class="br0">{</span><a href="../../../http:/en.cppreference.com/w/cpp/ranges-ranges-placeholder/begin"><span class="kw2885">ranges::<span class="me2">begin</span></span></a><span class="br0">(</span>r<span class="br0">)</span>, <a href="../../../http:/en.cppreference.com/w/cpp/ranges-ranges-placeholder/end"><span class="kw2887">ranges::<span class="me2">end</span></span></a><span class="br0">(</span>r<span class="br0">)</span>, n<span class="br0">}</span> <span class="br0">{</span><span class="br0">}</span>
 
    <span class="kw1">template</span><span class="sy1">&lt;</span><span class="coMULTI">/*different-from*/</span><span class="sy1">&lt;</span>subrange<span class="sy1">&gt;</span> PairLike<span class="sy1">&gt;</span>
      requires <span class="coMULTI">/*pair-like-convertible-from*/</span><span class="sy1">&lt;</span>PairLike, <span class="kw4">const</span> I<span class="sy3">&amp;</span>, <span class="kw4">const</span> S<span class="sy3">&amp;</span><span class="sy1">&gt;</span>
    <span class="kw4">constexpr</span> operator PairLike<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> I begin<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span> requires copyable<span class="sy1">&lt;</span>I<span class="sy1">&gt;</span><span class="sy4">;</span>
    <span class="br0">[</span><span class="br0">[</span>nodiscard<span class="br0">]</span><span class="br0">]</span> <span class="kw4">constexpr</span> I begin<span class="br0">(</span><span class="br0">)</span> requires <span class="br0">(</span><span class="sy3">!</span>copyable<span class="sy1">&lt;</span>I<span class="sy1">&gt;</span><span class="br0">)</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> S end<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> <span class="kw4">bool</span> empty<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> <span class="coMULTI">/*make-unsigned-like-t*/</span><span class="sy1">&lt;</span>iter_difference_t<span class="sy1">&lt;</span>I<span class="sy1">&gt;&gt;</span> size<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span>
      requires <span class="br0">(</span>K <span class="sy1">==</span> subrange_kind<span class="sy4">::</span><span class="me2">sized</span><span class="br0">)</span><span class="sy4">;</span>
 
    <span class="br0">[</span><span class="br0">[</span>nodiscard<span class="br0">]</span><span class="br0">]</span> <span class="kw4">constexpr</span> subrange next<span class="br0">(</span>iter_difference_t<span class="sy1">&lt;</span>I<span class="sy1">&gt;</span> n <span class="sy1">=</span> <span class="nu0">1</span><span class="br0">)</span> <span class="kw4">const</span> <span class="sy3">&amp;</span>
      requires forward_iterator<span class="sy1">&lt;</span>I<span class="sy1">&gt;</span><span class="sy4">;</span>
    <span class="br0">[</span><span class="br0">[</span>nodiscard<span class="br0">]</span><span class="br0">]</span> <span class="kw4">constexpr</span> subrange next<span class="br0">(</span>iter_difference_t<span class="sy1">&lt;</span>I<span class="sy1">&gt;</span> n <span class="sy1">=</span> <span class="nu0">1</span><span class="br0">)</span> <span class="sy3">&amp;&amp;</span><span class="sy4">;</span>
    <span class="br0">[</span><span class="br0">[</span>nodiscard<span class="br0">]</span><span class="br0">]</span> <span class="kw4">constexpr</span> subrange prev<span class="br0">(</span>iter_difference_t<span class="sy1">&lt;</span>I<span class="sy1">&gt;</span> n <span class="sy1">=</span> <span class="nu0">1</span><span class="br0">)</span> <span class="kw4">const</span>
      requires bidirectional_iterator<span class="sy1">&lt;</span>I<span class="sy1">&gt;</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> subrange<span class="sy3">&amp;</span> advance<span class="br0">(</span>iter_difference_t<span class="sy1">&lt;</span>I<span class="sy1">&gt;</span> n<span class="br0">)</span><span class="sy4">;</span>
  <span class="br0">}</span><span class="sy4">;</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span>input_or_output_iterator I, sentinel_for<span class="sy1">&lt;</span>I<span class="sy1">&gt;</span> S<span class="sy1">&gt;</span>
    subrange<span class="br0">(</span>I, S<span class="br0">)</span> <span class="sy2">-</span><span class="sy1">&gt;</span> subrange<span class="sy1">&lt;</span>I, S<span class="sy1">&gt;</span><span class="sy4">;</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span>input_or_output_iterator I, sentinel_for<span class="sy1">&lt;</span>I<span class="sy1">&gt;</span> S<span class="sy1">&gt;</span>
    subrange<span class="br0">(</span>I, S, <span class="coMULTI">/*make-unsigned-like-t*/</span><span class="sy1">&lt;</span>iter_difference_t<span class="sy1">&lt;</span>I<span class="sy1">&gt;&gt;</span><span class="br0">)</span> <span class="sy2">-</span><span class="sy1">&gt;</span>
      subrange<span class="sy1">&lt;</span>I, S, subrange_kind<span class="sy4">::</span><span class="me2">sized</span><span class="sy1">&gt;</span><span class="sy4">;</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span>borrowed_range R<span class="sy1">&gt;</span>
    subrange<span class="br0">(</span>R<span class="sy3">&amp;&amp;</span><span class="br0">)</span> <span class="sy2">-</span><span class="sy1">&gt;</span>
      subrange<span class="sy1">&lt;</span>iterator_t<span class="sy1">&lt;</span>R<span class="sy1">&gt;</span>, sentinel_t<span class="sy1">&lt;</span>R<span class="sy1">&gt;</span>,
               <span class="br0">(</span>sized_range<span class="sy1">&lt;</span>R<span class="sy1">&gt;</span> <span class="sy3">||</span> sized_sentinel_for<span class="sy1">&lt;</span>sentinel_t<span class="sy1">&lt;</span>R<span class="sy1">&gt;</span>, iterator_t<span class="sy1">&lt;</span>R<span class="sy1">&gt;&gt;</span><span class="br0">)</span>
                 <span class="sy4">?</span> subrange_kind<span class="sy4">::</span><span class="me2">sized</span> <span class="sy4">:</span> subrange_kind<span class="sy4">::</span><span class="me2">unsized</span><span class="sy1">&gt;</span><span class="sy4">;</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span>borrowed_range R<span class="sy1">&gt;</span>
    subrange<span class="br0">(</span>R<span class="sy3">&amp;&amp;</span>, <span class="coMULTI">/*make-unsigned-like-t*/</span><span class="sy1">&lt;</span>range_difference_t<span class="sy1">&lt;</span>R<span class="sy1">&gt;&gt;</span><span class="br0">)</span> <span class="sy2">-</span><span class="sy1">&gt;</span>
      subrange<span class="sy1">&lt;</span>iterator_t<span class="sy1">&lt;</span>R<span class="sy1">&gt;</span>, sentinel_t<span class="sy1">&lt;</span>R<span class="sy1">&gt;</span>, subrange_kind<span class="sy4">::</span><span class="me2">sized</span><span class="sy1">&gt;</span><span class="sy4">;</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span>size_t N, <span class="kw1">class</span> I, <span class="kw1">class</span> S, subrange_kind K<span class="sy1">&gt;</span>
    requires <span class="br0">(</span><span class="br0">(</span>N <span class="sy1">==</span> <span class="nu0">0</span> <span class="sy3">&amp;&amp;</span> copyable<span class="sy1">&lt;</span>I<span class="sy1">&gt;</span><span class="br0">)</span> <span class="sy3">||</span> N <span class="sy1">==</span> <span class="nu0">1</span><span class="br0">)</span>
    <span class="kw4">constexpr</span> <span class="kw4">auto</span> get<span class="br0">(</span><span class="kw4">const</span> subrange<span class="sy1">&lt;</span>I, S, K<span class="sy1">&gt;</span><span class="sy3">&amp;</span> r<span class="br0">)</span><span class="sy4">;</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span>size_t N, <span class="kw1">class</span> I, <span class="kw1">class</span> S, subrange_kind K<span class="sy1">&gt;</span>
    requires <span class="br0">(</span>N <span class="sy1">&lt;</span> <span class="nu0">2</span><span class="br0">)</span>
    <span class="kw4">constexpr</span> <span class="kw4">auto</span> get<span class="br0">(</span>subrange<span class="sy1">&lt;</span>I, S, K<span class="sy1">&gt;</span><span class="sy3">&amp;&amp;</span> r<span class="br0">)</span><span class="sy4">;</span>
<span class="br0">}</span>
 
<span class="kw1">namespace</span> std <span class="br0">{</span>
  <span class="kw1">using</span> ranges<span class="sy4">::</span><span class="me2">get</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<h4><span class="mw-headline" id="Class_std::ranges::dangling">Class <span class="t-lc"><a href="../ranges/dangling.html" title="cpp/ranges/dangling">std::ranges::dangling</a></span></span></h4>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">namespace</span> std<span class="sy4">::</span><span class="me2">ranges</span> <span class="br0">{</span>
  <span class="kw1">struct</span> dangling <span class="br0">{</span>
    <span class="kw4">constexpr</span> dangling<span class="br0">(</span><span class="br0">)</span> <span class="kw1">noexcept</span> <span class="sy1">=</span> <span class="kw1">default</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> dangling<span class="br0">(</span><span class="kw4">auto</span><span class="sy3">&amp;&amp;</span>...<span class="br0">)</span> <span class="kw1">noexcept</span> <span class="br0">{</span><span class="br0">}</span>
  <span class="br0">}</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<h4><span class="mw-headline" id="Class_template_std::ranges::empty_view">Class template <span class="t-lc"><a href="../ranges/empty_view.html" title="cpp/ranges/empty view">std::ranges::empty_view</a></span></span></h4>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">namespace</span> std<span class="sy4">::</span><span class="me2">ranges</span> <span class="br0">{</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> T<span class="sy1">&gt;</span>
    requires is_object_v<span class="sy1">&lt;</span>T<span class="sy1">&gt;</span>
  <span class="kw1">class</span> empty_view <span class="sy4">:</span> <span class="kw1">public</span> view_interface<span class="sy1">&lt;</span>empty_view<span class="sy1">&lt;</span>T<span class="sy1">&gt;&gt;</span> <span class="br0">{</span>
  <span class="kw1">public</span><span class="sy4">:</span>
    <span class="kw4">static</span> <span class="kw4">constexpr</span> T<span class="sy2">*</span> begin<span class="br0">(</span><span class="br0">)</span> <span class="kw1">noexcept</span> <span class="br0">{</span> <span class="kw1">return</span> nullptr<span class="sy4">;</span> <span class="br0">}</span>
    <span class="kw4">static</span> <span class="kw4">constexpr</span> T<span class="sy2">*</span> end<span class="br0">(</span><span class="br0">)</span> <span class="kw1">noexcept</span> <span class="br0">{</span> <span class="kw1">return</span> nullptr<span class="sy4">;</span> <span class="br0">}</span>
    <span class="kw4">static</span> <span class="kw4">constexpr</span> T<span class="sy2">*</span> data<span class="br0">(</span><span class="br0">)</span> <span class="kw1">noexcept</span> <span class="br0">{</span> <span class="kw1">return</span> nullptr<span class="sy4">;</span> <span class="br0">}</span>
    <span class="kw4">static</span> <span class="kw4">constexpr</span> size_t size<span class="br0">(</span><span class="br0">)</span> <span class="kw1">noexcept</span> <span class="br0">{</span> <span class="kw1">return</span> <span class="nu0">0</span><span class="sy4">;</span> <span class="br0">}</span>
    <span class="kw4">static</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> empty<span class="br0">(</span><span class="br0">)</span> <span class="kw1">noexcept</span> <span class="br0">{</span> <span class="kw1">return</span> <span class="kw2">true</span><span class="sy4">;</span> <span class="br0">}</span>
  <span class="br0">}</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<h4><span class="mw-headline" id="Class_template_std::ranges::single_view">Class template <span class="t-lc">std::ranges::single_view</span></span></h4>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">namespace</span> std<span class="sy4">::</span><span class="me2">ranges</span> <span class="br0">{</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span>copy_constructible T<span class="sy1">&gt;</span>
    requires is_object_v<span class="sy1">&lt;</span>T<span class="sy1">&gt;</span>
  <span class="kw1">class</span> single_view <span class="sy4">:</span> <span class="kw1">public</span> view_interface<span class="sy1">&lt;</span>single_view<span class="sy1">&lt;</span>T<span class="sy1">&gt;&gt;</span> <span class="br0">{</span>
  <span class="kw1">private</span><span class="sy4">:</span>
    <span class="coMULTI">/*copyable-box*/</span><span class="sy1">&lt;</span>T<span class="sy1">&gt;</span> value_<span class="sy4">;</span>             <span class="co1">// exposition only</span>
 
  <span class="kw1">public</span><span class="sy4">:</span>
    single_view<span class="br0">(</span><span class="br0">)</span> requires default_initializable<span class="sy1">&lt;</span>T<span class="sy1">&gt;</span> <span class="sy1">=</span> <span class="kw1">default</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> <span class="kw1">explicit</span> single_view<span class="br0">(</span><span class="kw4">const</span> T<span class="sy3">&amp;</span> t<span class="br0">)</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> <span class="kw1">explicit</span> single_view<span class="br0">(</span>T<span class="sy3">&amp;&amp;</span> t<span class="br0">)</span><span class="sy4">;</span>
    <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span>... <span class="me1">Args</span><span class="sy1">&gt;</span>
      requires constructible_from<span class="sy1">&lt;</span>T, Args...<span class="sy1">&gt;</span>
    <span class="kw4">constexpr</span> <span class="kw1">explicit</span> single_view<span class="br0">(</span>in_place_t, Args<span class="sy3">&amp;&amp;</span>... <span class="me1">args</span><span class="br0">)</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> T<span class="sy2">*</span> begin<span class="br0">(</span><span class="br0">)</span> <span class="kw1">noexcept</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> <span class="kw4">const</span> T<span class="sy2">*</span> begin<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span> <span class="kw1">noexcept</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> T<span class="sy2">*</span> end<span class="br0">(</span><span class="br0">)</span> <span class="kw1">noexcept</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> <span class="kw4">const</span> T<span class="sy2">*</span> end<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span> <span class="kw1">noexcept</span><span class="sy4">;</span>
    <span class="kw4">static</span> <span class="kw4">constexpr</span> size_t size<span class="br0">(</span><span class="br0">)</span> <span class="kw1">noexcept</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> T<span class="sy2">*</span> data<span class="br0">(</span><span class="br0">)</span> <span class="kw1">noexcept</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> <span class="kw4">const</span> T<span class="sy2">*</span> data<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span> <span class="kw1">noexcept</span><span class="sy4">;</span>
  <span class="br0">}</span><span class="sy4">;</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> T<span class="sy1">&gt;</span>
    single_view<span class="br0">(</span>T<span class="br0">)</span> <span class="sy2">-</span><span class="sy1">&gt;</span> single_view<span class="sy1">&lt;</span>T<span class="sy1">&gt;</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<h4><span class="mw-headline" id="Class_template_std::ranges::iota_view">Class template <span class="t-lc"><a href="../ranges/iota_view.html" title="cpp/ranges/iota view">std::ranges::iota_view</a></span></span></h4>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">namespace</span> std<span class="sy4">::</span><span class="me2">ranges</span> <span class="br0">{</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> I<span class="sy1">&gt;</span>
    concept decrementable <span class="sy1">=</span> <span class="coMULTI">/* see description */</span><span class="sy4">;</span>  <span class="co1">// exposition only</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> I<span class="sy1">&gt;</span>
    concept advanceable <span class="sy1">=</span> <span class="coMULTI">/* see description */</span><span class="sy4">;</span>    <span class="co1">// exposition only</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span>weakly_incrementable W, semiregular Bound <span class="sy1">=</span> unreachable_sentinel_t<span class="sy1">&gt;</span>
    requires <span class="coMULTI">/*weakly-equality-comparable-with*/</span><span class="sy1">&lt;</span>W, Bound<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> copyable<span class="sy1">&lt;</span>W<span class="sy1">&gt;</span>
  <span class="kw1">class</span> iota_view <span class="sy4">:</span> <span class="kw1">public</span> view_interface<span class="sy1">&lt;</span>iota_view<span class="sy1">&lt;</span>W, Bound<span class="sy1">&gt;&gt;</span> <span class="br0">{</span>
  <span class="kw1">private</span><span class="sy4">:</span>
    <span class="co1">// class iota_view::iterator</span>
    <span class="kw1">struct</span> iterator<span class="sy4">;</span>                    <span class="co1">// exposition only</span>
 
    <span class="co1">// class iota_view::sentinel</span>
    <span class="kw1">struct</span> sentinel<span class="sy4">;</span>                    <span class="co1">// exposition only</span>
 
    W value_ <span class="sy1">=</span> W<span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>                     <span class="co1">// exposition only</span>
    Bound bound_ <span class="sy1">=</span> Bound<span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>             <span class="co1">// exposition only</span>
 
  <span class="kw1">public</span><span class="sy4">:</span>
    iota_view<span class="br0">(</span><span class="br0">)</span> requires default_initializable<span class="sy1">&lt;</span>W<span class="sy1">&gt;</span> <span class="sy1">=</span> <span class="kw1">default</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> <span class="kw1">explicit</span> iota_view<span class="br0">(</span>W value<span class="br0">)</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> iota_view<span class="br0">(</span>type_identity_t<span class="sy1">&lt;</span>W<span class="sy1">&gt;</span> value, type_identity_t<span class="sy1">&lt;</span>Bound<span class="sy1">&gt;</span> bound<span class="br0">)</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> iota_view<span class="br0">(</span>iterator first, <span class="coMULTI">/* see description */</span> last<span class="br0">)</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> iterator begin<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> <span class="kw4">auto</span> end<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> iterator end<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span> requires same_as<span class="sy1">&lt;</span>W, Bound<span class="sy1">&gt;</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> <span class="kw4">auto</span> size<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span> requires <span class="coMULTI">/* see description */</span><span class="sy4">;</span>
  <span class="br0">}</span><span class="sy4">;</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> W, <span class="kw1">class</span> Bound<span class="sy1">&gt;</span>
    requires <span class="br0">(</span><span class="sy3">!</span><span class="coMULTI">/*is-integer-like*/</span><span class="sy1">&lt;</span>W<span class="sy1">&gt;</span> <span class="sy3">||</span> <span class="sy3">!</span><span class="coMULTI">/*is-integer-like*/</span><span class="sy1">&lt;</span>Bound<span class="sy1">&gt;</span> <span class="sy3">||</span>
              <span class="br0">(</span><span class="coMULTI">/*is-signed-integer-like*/</span><span class="sy1">&lt;</span>W<span class="sy1">&gt;</span> <span class="sy1">==</span> <span class="coMULTI">/*is-signed-integer-like*/</span><span class="sy1">&lt;</span>Bound<span class="sy1">&gt;</span><span class="br0">)</span><span class="br0">)</span>
    iota_view<span class="br0">(</span>W, Bound<span class="br0">)</span> <span class="sy2">-</span><span class="sy1">&gt;</span> iota_view<span class="sy1">&lt;</span>W, Bound<span class="sy1">&gt;</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<h4><span class="mw-headline" id="Class_std::ranges::iota_view::iterator">Class <span class="t-lc">std::ranges::iota_view::iterator</span></span></h4>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">namespace</span> std<span class="sy4">::</span><span class="me2">ranges</span> <span class="br0">{</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span>weakly_incrementable W, semiregular Bound<span class="sy1">&gt;</span>
    requires <span class="coMULTI">/*weakly-equality-comparable-with*/</span><span class="sy1">&lt;</span>W, Bound<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> copyable<span class="sy1">&lt;</span>W<span class="sy1">&gt;</span>
  <span class="kw1">struct</span> iota_view<span class="sy1">&lt;</span>W, Bound<span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">iterator</span> <span class="br0">{</span>
  <span class="kw1">private</span><span class="sy4">:</span>
    W value_ <span class="sy1">=</span> W<span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>             <span class="co1">// exposition only</span>
  <span class="kw1">public</span><span class="sy4">:</span>
    <span class="kw1">using</span> iterator_concept <span class="sy1">=</span> <span class="coMULTI">/* see description */</span><span class="sy4">;</span>
    <span class="kw1">using</span> iterator_category <span class="sy1">=</span> input_iterator_tag<span class="sy4">;</span> <span class="co1">// present only if W models incrementable</span>
    <span class="kw1">using</span> value_type <span class="sy1">=</span> W<span class="sy4">;</span>
    <span class="kw1">using</span> difference_type <span class="sy1">=</span> <span class="coMULTI">/*IOTA-DIFF-T*/</span><span class="br0">(</span>W<span class="br0">)</span><span class="sy4">;</span>
 
    iterator<span class="br0">(</span><span class="br0">)</span> requires default_initializable<span class="sy1">&lt;</span>W<span class="sy1">&gt;</span> <span class="sy1">=</span> <span class="kw1">default</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> <span class="kw1">explicit</span> iterator<span class="br0">(</span>W value<span class="br0">)</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> W operator<span class="sy2">*</span><span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span> <span class="kw1">noexcept</span><span class="br0">(</span>is_nothrow_copy_constructible_v<span class="sy1">&lt;</span>W<span class="sy1">&gt;</span><span class="br0">)</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> iterator<span class="sy3">&amp;</span> operator<span class="sy2">++</span><span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> <span class="kw4">void</span> operator<span class="sy2">++</span><span class="br0">(</span><span class="kw4">int</span><span class="br0">)</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> iterator operator<span class="sy2">++</span><span class="br0">(</span><span class="kw4">int</span><span class="br0">)</span> requires incrementable<span class="sy1">&lt;</span>W<span class="sy1">&gt;</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> iterator<span class="sy3">&amp;</span> operator<span class="sy2">--</span><span class="br0">(</span><span class="br0">)</span> requires <span class="coMULTI">/*decrementable*/</span><span class="sy1">&lt;</span>W<span class="sy1">&gt;</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> iterator operator<span class="sy2">--</span><span class="br0">(</span><span class="kw4">int</span><span class="br0">)</span> requires <span class="coMULTI">/*decrementable*/</span><span class="sy1">&lt;</span>W<span class="sy1">&gt;</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> iterator<span class="sy3">&amp;</span> operator<span class="sy2">+</span><span class="sy1">=</span><span class="br0">(</span>difference_type n<span class="br0">)</span>
      requires <span class="coMULTI">/*advanceable*/</span><span class="sy1">&lt;</span>W<span class="sy1">&gt;</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> iterator<span class="sy3">&amp;</span> operator<span class="sy2">-</span><span class="sy1">=</span><span class="br0">(</span>difference_type n<span class="br0">)</span>
      requires <span class="coMULTI">/*advanceable*/</span><span class="sy1">&lt;</span>W<span class="sy1">&gt;</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> W operator<span class="br0">[</span><span class="br0">]</span><span class="br0">(</span>difference_type n<span class="br0">)</span> <span class="kw4">const</span>
      requires <span class="coMULTI">/*advanceable*/</span><span class="sy1">&lt;</span>W<span class="sy1">&gt;</span><span class="sy4">;</span>
 
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> operator<span class="sy1">==</span><span class="br0">(</span><span class="kw4">const</span> iterator<span class="sy3">&amp;</span> x, <span class="kw4">const</span> iterator<span class="sy3">&amp;</span> y<span class="br0">)</span>
      requires equality_comparable<span class="sy1">&lt;</span>W<span class="sy1">&gt;</span><span class="sy4">;</span>
 
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> operator<span class="sy1">&lt;</span><span class="br0">(</span><span class="kw4">const</span> iterator<span class="sy3">&amp;</span> x, <span class="kw4">const</span> iterator<span class="sy3">&amp;</span> y<span class="br0">)</span>
      requires totally_ordered<span class="sy1">&lt;</span>W<span class="sy1">&gt;</span><span class="sy4">;</span>
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> operator<span class="sy1">&gt;</span><span class="br0">(</span><span class="kw4">const</span> iterator<span class="sy3">&amp;</span> x, <span class="kw4">const</span> iterator<span class="sy3">&amp;</span> y<span class="br0">)</span>
      requires totally_ordered<span class="sy1">&lt;</span>W<span class="sy1">&gt;</span><span class="sy4">;</span>
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> operator<span class="sy1">&lt;=</span><span class="br0">(</span><span class="kw4">const</span> iterator<span class="sy3">&amp;</span> x, <span class="kw4">const</span> iterator<span class="sy3">&amp;</span> y<span class="br0">)</span>
      requires totally_ordered<span class="sy1">&lt;</span>W<span class="sy1">&gt;</span><span class="sy4">;</span>
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> operator<span class="sy1">&gt;=</span><span class="br0">(</span><span class="kw4">const</span> iterator<span class="sy3">&amp;</span> x, <span class="kw4">const</span> iterator<span class="sy3">&amp;</span> y<span class="br0">)</span>
      requires totally_ordered<span class="sy1">&lt;</span>W<span class="sy1">&gt;</span><span class="sy4">;</span>
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> <span class="kw4">auto</span> operator<span class="sy1">&lt;=&gt;</span><span class="br0">(</span><span class="kw4">const</span> iterator<span class="sy3">&amp;</span> x, <span class="kw4">const</span> iterator<span class="sy3">&amp;</span> y<span class="br0">)</span>
      requires totally_ordered<span class="sy1">&lt;</span>W<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> three_way_comparable<span class="sy1">&lt;</span>W<span class="sy1">&gt;</span><span class="sy4">;</span>
 
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> iterator operator<span class="sy2">+</span><span class="br0">(</span>iterator i, difference_type n<span class="br0">)</span>
      requires <span class="coMULTI">/*advanceable*/</span><span class="sy1">&lt;</span>W<span class="sy1">&gt;</span><span class="sy4">;</span>
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> iterator operator<span class="sy2">+</span><span class="br0">(</span>difference_type n, iterator i<span class="br0">)</span>
      requires <span class="coMULTI">/*advanceable*/</span><span class="sy1">&lt;</span>W<span class="sy1">&gt;</span><span class="sy4">;</span>
 
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> iterator operator<span class="sy2">-</span><span class="br0">(</span>iterator i, difference_type n<span class="br0">)</span>
      requires <span class="coMULTI">/*advanceable*/</span><span class="sy1">&lt;</span>W<span class="sy1">&gt;</span><span class="sy4">;</span>
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> difference_type operator<span class="sy2">-</span><span class="br0">(</span><span class="kw4">const</span> iterator<span class="sy3">&amp;</span> x, <span class="kw4">const</span> iterator<span class="sy3">&amp;</span> y<span class="br0">)</span>
      requires <span class="coMULTI">/*advanceable*/</span><span class="sy1">&lt;</span>W<span class="sy1">&gt;</span><span class="sy4">;</span>
  <span class="br0">}</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<h4><span class="mw-headline" id="Class_std::ranges::iota_view::sentinel">Class <span class="t-lc">std::ranges::iota_view::sentinel</span></span></h4>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">namespace</span> std<span class="sy4">::</span><span class="me2">ranges</span> <span class="br0">{</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span>weakly_incrementable W, semiregular Bound<span class="sy1">&gt;</span>
    requires <span class="coMULTI">/*weakly-equality-comparable-with*/</span><span class="sy1">&lt;</span>W, Bound<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> copyable<span class="sy1">&lt;</span>W<span class="sy1">&gt;</span>
  <span class="kw1">struct</span> iota_view<span class="sy1">&lt;</span>W, Bound<span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">sentinel</span> <span class="br0">{</span>
  <span class="kw1">private</span><span class="sy4">:</span>
    Bound bound_ <span class="sy1">=</span> Bound<span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>     <span class="co1">// exposition only</span>
  <span class="kw1">public</span><span class="sy4">:</span>
    sentinel<span class="br0">(</span><span class="br0">)</span> <span class="sy1">=</span> <span class="kw1">default</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> <span class="kw1">explicit</span> sentinel<span class="br0">(</span>Bound bound<span class="br0">)</span><span class="sy4">;</span>
 
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> operator<span class="sy1">==</span><span class="br0">(</span><span class="kw4">const</span> iterator<span class="sy3">&amp;</span> x, <span class="kw4">const</span> sentinel<span class="sy3">&amp;</span> y<span class="br0">)</span><span class="sy4">;</span>
 
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> iter_difference_t<span class="sy1">&lt;</span>W<span class="sy1">&gt;</span> operator<span class="sy2">-</span><span class="br0">(</span><span class="kw4">const</span> iterator<span class="sy3">&amp;</span> x, <span class="kw4">const</span> sentinel<span class="sy3">&amp;</span> y<span class="br0">)</span>
      requires sized_sentinel_for<span class="sy1">&lt;</span>Bound, W<span class="sy1">&gt;</span><span class="sy4">;</span>
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> iter_difference_t<span class="sy1">&lt;</span>W<span class="sy1">&gt;</span> operator<span class="sy2">-</span><span class="br0">(</span><span class="kw4">const</span> sentinel<span class="sy3">&amp;</span> x, <span class="kw4">const</span> iterator<span class="sy3">&amp;</span> y<span class="br0">)</span>
      requires sized_sentinel_for<span class="sy1">&lt;</span>Bound, W<span class="sy1">&gt;</span><span class="sy4">;</span>
  <span class="br0">}</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<h4><span class="mw-headline" id="Class_template_std::ranges::basic_istream_view">Class template <span class="t-lc">std::ranges::basic_istream_view</span></span></h4>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">namespace</span> std<span class="sy4">::</span><span class="me2">ranges</span> <span class="br0">{</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> Val, <span class="kw1">class</span> CharT, <span class="kw1">class</span> Traits<span class="sy1">&gt;</span>
    concept <span class="coMULTI">/*stream-extractable*/</span> <span class="sy1">=</span>                <span class="co1">// exposition only</span>
      requires<span class="br0">(</span>basic_istream<span class="sy1">&lt;</span>CharT, Traits<span class="sy1">&gt;</span><span class="sy3">&amp;</span> is, Val<span class="sy3">&amp;</span> t<span class="br0">)</span> <span class="br0">{</span>
         is <span class="sy1">&gt;&gt;</span> t<span class="sy4">;</span>
      <span class="br0">}</span><span class="sy4">;</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span>movable Val, <span class="kw1">class</span> CharT, <span class="kw1">class</span> Traits <span class="sy1">=</span> char_traits<span class="sy1">&lt;</span>CharT<span class="sy1">&gt;&gt;</span>
    requires default_initializable<span class="sy1">&lt;</span>Val<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
             <span class="coMULTI">/*stream-extractable*/</span><span class="sy1">&lt;</span>Val, CharT, Traits<span class="sy1">&gt;</span>
  <span class="kw1">class</span> basic_istream_view <span class="sy4">:</span>
    <span class="kw1">public</span> view_interface<span class="sy1">&lt;</span>basic_istream_view<span class="sy1">&lt;</span>Val, CharT, Traits<span class="sy1">&gt;&gt;</span> <span class="br0">{</span>
  <span class="kw1">public</span><span class="sy4">:</span>
    <span class="kw4">constexpr</span> <span class="kw1">explicit</span> basic_istream_view<span class="br0">(</span>basic_istream<span class="sy1">&lt;</span>CharT, Traits<span class="sy1">&gt;</span><span class="sy3">&amp;</span> stream<span class="br0">)</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> <span class="kw4">auto</span> begin<span class="br0">(</span><span class="br0">)</span> <span class="br0">{</span>
      <span class="sy2">*</span>stream_ <span class="sy1">&gt;&gt;</span> value_<span class="sy4">;</span>
      <span class="kw1">return</span> iterator<span class="br0">{</span><span class="sy2">*</span>this<span class="br0">}</span><span class="sy4">;</span>
    <span class="br0">}</span>
 
    <span class="kw4">constexpr</span> default_sentinel_t end<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span> <span class="kw1">noexcept</span><span class="sy4">;</span>
 
  <span class="kw1">private</span><span class="sy4">:</span>
    <span class="kw1">struct</span> iterator<span class="sy4">;</span>                            <span class="co1">// exposition only</span>
    basic_istream<span class="sy1">&lt;</span>CharT, Traits<span class="sy1">&gt;</span><span class="sy2">*</span> stream_<span class="sy4">;</span>      <span class="co1">// exposition only</span>
    Val value_ <span class="sy1">=</span> Val<span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>                         <span class="co1">// exposition only</span>
  <span class="br0">}</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<h4><span class="mw-headline" id="Class_template_std::ranges::basic_istream_view::iterator">Class template <span class="t-lc">std::ranges::basic_istream_view::iterator</span></span></h4>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">namespace</span> std<span class="sy4">::</span><span class="me2">ranges</span> <span class="br0">{</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span>movable Val, <span class="kw1">class</span> CharT, <span class="kw1">class</span> Traits<span class="sy1">&gt;</span>
    requires default_initializable<span class="sy1">&lt;</span>Val<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
             <span class="coMULTI">/*stream-extractable*/</span><span class="sy1">&lt;</span>Val, CharT, Traits<span class="sy1">&gt;</span>
  <span class="kw1">class</span> basic_istream_view<span class="sy1">&lt;</span>Val, CharT, Traits<span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">iterator</span> <span class="br0">{</span>
  <span class="kw1">public</span><span class="sy4">:</span>
    <span class="kw1">using</span> iterator_concept <span class="sy1">=</span> input_iterator_tag<span class="sy4">;</span>
    <span class="kw1">using</span> difference_type <span class="sy1">=</span> ptrdiff_t<span class="sy4">;</span>
    <span class="kw1">using</span> value_type <span class="sy1">=</span> Val<span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> <span class="kw1">explicit</span> iterator<span class="br0">(</span>basic_istream_view<span class="sy3">&amp;</span> parent<span class="br0">)</span> <span class="kw1">noexcept</span><span class="sy4">;</span>
 
    iterator<span class="br0">(</span><span class="kw4">const</span> iterator<span class="sy3">&amp;</span><span class="br0">)</span> <span class="sy1">=</span> delete<span class="sy4">;</span>
    iterator<span class="br0">(</span>iterator<span class="sy3">&amp;&amp;</span><span class="br0">)</span> <span class="sy1">=</span> <span class="kw1">default</span><span class="sy4">;</span>
 
    iterator<span class="sy3">&amp;</span> operator<span class="sy1">=</span><span class="br0">(</span><span class="kw4">const</span> iterator<span class="sy3">&amp;</span><span class="br0">)</span> <span class="sy1">=</span> delete<span class="sy4">;</span>
    iterator<span class="sy3">&amp;</span> operator<span class="sy1">=</span><span class="br0">(</span>iterator<span class="sy3">&amp;&amp;</span><span class="br0">)</span> <span class="sy1">=</span> <span class="kw1">default</span><span class="sy4">;</span>
 
    iterator<span class="sy3">&amp;</span> operator<span class="sy2">++</span><span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>
    <span class="kw4">void</span> operator<span class="sy2">++</span><span class="br0">(</span><span class="kw4">int</span><span class="br0">)</span><span class="sy4">;</span>
 
    Val<span class="sy3">&amp;</span> operator<span class="sy2">*</span><span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span><span class="sy4">;</span>
 
    <span class="kw1">friend</span> <span class="kw4">bool</span> operator<span class="sy1">==</span><span class="br0">(</span><span class="kw4">const</span> iterator<span class="sy3">&amp;</span> x, default_sentinel_t<span class="br0">)</span><span class="sy4">;</span>
 
  <span class="kw1">private</span><span class="sy4">:</span>
    basic_istream_view<span class="sy2">*</span> parent_<span class="sy4">;</span>                                <span class="co1">// exposition only</span>
  <span class="br0">}</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<h4><span class="mw-headline" id="Class_template_std::ranges::ref_view">Class template <span class="t-lc"><a href="../ranges/ref_view.html" title="cpp/ranges/ref view">std::ranges::ref_view</a></span></span></h4>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">namespace</span> std<span class="sy4">::</span><span class="me2">ranges</span> <span class="br0">{</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span>range R<span class="sy1">&gt;</span>
    requires is_object_v<span class="sy1">&lt;</span>R<span class="sy1">&gt;</span>
  <span class="kw1">class</span> ref_view <span class="sy4">:</span> <span class="kw1">public</span> view_interface<span class="sy1">&lt;</span>ref_view<span class="sy1">&lt;</span>R<span class="sy1">&gt;&gt;</span> <span class="br0">{</span>
  <span class="kw1">private</span><span class="sy4">:</span>
    R<span class="sy2">*</span> r_<span class="sy4">;</span>                      <span class="co1">// exposition only</span>
  <span class="kw1">public</span><span class="sy4">:</span>
    <span class="kw1">template</span><span class="sy1">&lt;</span><span class="coMULTI">/*different-from*/</span><span class="sy1">&lt;</span>ref_view<span class="sy1">&gt;</span> T<span class="sy1">&gt;</span>
      requires <span class="coMULTI">/* see description */</span>
    <span class="kw4">constexpr</span> ref_view<span class="br0">(</span>T<span class="sy3">&amp;&amp;</span> t<span class="br0">)</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> R<span class="sy3">&amp;</span> base<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span> <span class="br0">{</span> <span class="kw1">return</span> <span class="sy2">*</span>r_<span class="sy4">;</span> <span class="br0">}</span>
 
    <span class="kw4">constexpr</span> iterator_t<span class="sy1">&lt;</span>R<span class="sy1">&gt;</span> begin<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span> <span class="br0">{</span> <span class="kw1">return</span> <a href="../../../http:/en.cppreference.com/w/cpp/ranges-ranges-placeholder/begin"><span class="kw2885">ranges::<span class="me2">begin</span></span></a><span class="br0">(</span><span class="sy2">*</span>r_<span class="br0">)</span><span class="sy4">;</span> <span class="br0">}</span>
    <span class="kw4">constexpr</span> sentinel_t<span class="sy1">&lt;</span>R<span class="sy1">&gt;</span> end<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span> <span class="br0">{</span> <span class="kw1">return</span> <a href="../../../http:/en.cppreference.com/w/cpp/ranges-ranges-placeholder/end"><span class="kw2887">ranges::<span class="me2">end</span></span></a><span class="br0">(</span><span class="sy2">*</span>r_<span class="br0">)</span><span class="sy4">;</span> <span class="br0">}</span>
 
    <span class="kw4">constexpr</span> <span class="kw4">bool</span> empty<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span>
      requires requires <span class="br0">{</span> <a href="../ranges/empty.html"><span class="kw3105">ranges::<span class="me2">empty</span></span></a><span class="br0">(</span><span class="sy2">*</span>r_<span class="br0">)</span><span class="sy4">;</span> <span class="br0">}</span>
    <span class="br0">{</span> <span class="kw1">return</span> <a href="../ranges/empty.html"><span class="kw3105">ranges::<span class="me2">empty</span></span></a><span class="br0">(</span><span class="sy2">*</span>r_<span class="br0">)</span><span class="sy4">;</span> <span class="br0">}</span>
 
    <span class="kw4">constexpr</span> <span class="kw4">auto</span> size<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span> requires sized_range<span class="sy1">&lt;</span>R<span class="sy1">&gt;</span>
    <span class="br0">{</span> <span class="kw1">return</span> <a href="../ranges/size.html"><span class="kw3103">ranges::<span class="me2">size</span></span></a><span class="br0">(</span><span class="sy2">*</span>r_<span class="br0">)</span><span class="sy4">;</span> <span class="br0">}</span>
 
    <span class="kw4">constexpr</span> <span class="kw4">auto</span> data<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span> requires contiguous_range<span class="sy1">&lt;</span>R<span class="sy1">&gt;</span>
    <span class="br0">{</span> <span class="kw1">return</span> <a href="../../../http:/en.cppreference.com/w/cpp/ranges-ranges-placeholder/data"><span class="kw2891">ranges::<span class="me2">data</span></span></a><span class="br0">(</span><span class="sy2">*</span>r_<span class="br0">)</span><span class="sy4">;</span> <span class="br0">}</span>
  <span class="br0">}</span><span class="sy4">;</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> R<span class="sy1">&gt;</span>
    ref_view<span class="br0">(</span>R<span class="sy3">&amp;</span><span class="br0">)</span> <span class="sy2">-</span><span class="sy1">&gt;</span> ref_view<span class="sy1">&lt;</span>R<span class="sy1">&gt;</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<h4><span class="mw-headline" id="Class_template_std::ranges::owning_view">Class template <span class="t-lc">std::ranges::owning_view</span></span></h4>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">namespace</span> std<span class="sy4">::</span><span class="me2">ranges</span> <span class="br0">{</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span>range R<span class="sy1">&gt;</span>
    requires movable<span class="sy1">&lt;</span>R<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> <span class="br0">(</span><span class="sy3">!</span><span class="coMULTI">/*is-initializer-list*/</span><span class="sy1">&lt;</span>R<span class="sy1">&gt;</span><span class="br0">)</span>
  <span class="kw1">class</span> owning_view <span class="sy4">:</span> <span class="kw1">public</span> view_interface<span class="sy1">&lt;</span>owning_view<span class="sy1">&lt;</span>R<span class="sy1">&gt;&gt;</span> <span class="br0">{</span>
  <span class="kw1">private</span><span class="sy4">:</span>
    R r_ <span class="sy1">=</span> R<span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>         <span class="co1">// exposition only</span>
  <span class="kw1">public</span><span class="sy4">:</span>
    owning_view<span class="br0">(</span><span class="br0">)</span> requires default_initializable<span class="sy1">&lt;</span>R<span class="sy1">&gt;</span> <span class="sy1">=</span> <span class="kw1">default</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> owning_view<span class="br0">(</span>R<span class="sy3">&amp;&amp;</span> t<span class="br0">)</span><span class="sy4">;</span>
 
    owning_view<span class="br0">(</span>owning_view<span class="sy3">&amp;&amp;</span><span class="br0">)</span> <span class="sy1">=</span> <span class="kw1">default</span><span class="sy4">;</span>
    owning_view<span class="sy3">&amp;</span> operator<span class="sy1">=</span><span class="br0">(</span>owning_view<span class="sy3">&amp;&amp;</span><span class="br0">)</span> <span class="sy1">=</span> <span class="kw1">default</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> R<span class="sy3">&amp;</span> base<span class="br0">(</span><span class="br0">)</span> <span class="sy3">&amp;</span> <span class="kw1">noexcept</span> <span class="br0">{</span> <span class="kw1">return</span> r_<span class="sy4">;</span> <span class="br0">}</span>
    <span class="kw4">constexpr</span> <span class="kw4">const</span> R<span class="sy3">&amp;</span> base<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span><span class="sy3">&amp;</span> <span class="kw1">noexcept</span> <span class="br0">{</span> <span class="kw1">return</span> r_<span class="sy4">;</span> <span class="br0">}</span>
    <span class="kw4">constexpr</span> R<span class="sy3">&amp;&amp;</span> base<span class="br0">(</span><span class="br0">)</span> <span class="sy3">&amp;&amp;</span> <span class="kw1">noexcept</span> <span class="br0">{</span> <span class="kw1">return</span> std<span class="sy4">::</span><span class="me2">move</span><span class="br0">(</span>r_<span class="br0">)</span><span class="sy4">;</span> <span class="br0">}</span>
    <span class="kw4">constexpr</span> <span class="kw4">const</span> R<span class="sy3">&amp;&amp;</span> base<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span><span class="sy3">&amp;&amp;</span> <span class="kw1">noexcept</span> <span class="br0">{</span> <span class="kw1">return</span> std<span class="sy4">::</span><span class="me2">move</span><span class="br0">(</span>r_<span class="br0">)</span><span class="sy4">;</span> <span class="br0">}</span>
 
    <span class="kw4">constexpr</span> iterator_t<span class="sy1">&lt;</span>R<span class="sy1">&gt;</span> begin<span class="br0">(</span><span class="br0">)</span> <span class="br0">{</span> <span class="kw1">return</span> <a href="../../../http:/en.cppreference.com/w/cpp/ranges-ranges-placeholder/begin"><span class="kw2885">ranges::<span class="me2">begin</span></span></a><span class="br0">(</span>r_<span class="br0">)</span><span class="sy4">;</span> <span class="br0">}</span>
    <span class="kw4">constexpr</span> sentinel_t<span class="sy1">&lt;</span>R<span class="sy1">&gt;</span> end<span class="br0">(</span><span class="br0">)</span> <span class="br0">{</span> <span class="kw1">return</span> <a href="../../../http:/en.cppreference.com/w/cpp/ranges-ranges-placeholder/end"><span class="kw2887">ranges::<span class="me2">end</span></span></a><span class="br0">(</span>r_<span class="br0">)</span><span class="sy4">;</span> <span class="br0">}</span>
 
    <span class="kw4">constexpr</span> <span class="kw4">auto</span> begin<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span> requires range<span class="sy1">&lt;</span><span class="kw4">const</span> R<span class="sy1">&gt;</span>
    <span class="br0">{</span> <span class="kw1">return</span> <a href="../../../http:/en.cppreference.com/w/cpp/ranges-ranges-placeholder/begin"><span class="kw2885">ranges::<span class="me2">begin</span></span></a><span class="br0">(</span>r_<span class="br0">)</span><span class="sy4">;</span> <span class="br0">}</span>
    <span class="kw4">constexpr</span> <span class="kw4">auto</span> end<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span> requires range<span class="sy1">&lt;</span><span class="kw4">const</span> R<span class="sy1">&gt;</span>
    <span class="br0">{</span> <span class="kw1">return</span> <a href="../../../http:/en.cppreference.com/w/cpp/ranges-ranges-placeholder/end"><span class="kw2887">ranges::<span class="me2">end</span></span></a><span class="br0">(</span>r_<span class="br0">)</span><span class="sy4">;</span> <span class="br0">}</span>
 
    <span class="kw4">constexpr</span> <span class="kw4">bool</span> empty<span class="br0">(</span><span class="br0">)</span> requires requires <span class="br0">{</span> <a href="../ranges/empty.html"><span class="kw3105">ranges::<span class="me2">empty</span></span></a><span class="br0">(</span>r_<span class="br0">)</span><span class="sy4">;</span> <span class="br0">}</span>
    <span class="br0">{</span> <span class="kw1">return</span> <a href="../ranges/empty.html"><span class="kw3105">ranges::<span class="me2">empty</span></span></a><span class="br0">(</span>r_<span class="br0">)</span><span class="sy4">;</span> <span class="br0">}</span>
    <span class="kw4">constexpr</span> <span class="kw4">bool</span> empty<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span> requires requires <span class="br0">{</span> <a href="../ranges/empty.html"><span class="kw3105">ranges::<span class="me2">empty</span></span></a><span class="br0">(</span>r_<span class="br0">)</span><span class="sy4">;</span> <span class="br0">}</span>
    <span class="br0">{</span> <span class="kw1">return</span> <a href="../ranges/empty.html"><span class="kw3105">ranges::<span class="me2">empty</span></span></a><span class="br0">(</span>r_<span class="br0">)</span><span class="sy4">;</span> <span class="br0">}</span>
 
    <span class="kw4">constexpr</span> <span class="kw4">auto</span> size<span class="br0">(</span><span class="br0">)</span> requires sized_range<span class="sy1">&lt;</span>R<span class="sy1">&gt;</span>
    <span class="br0">{</span> <span class="kw1">return</span> <a href="../ranges/size.html"><span class="kw3103">ranges::<span class="me2">size</span></span></a><span class="br0">(</span>r_<span class="br0">)</span><span class="sy4">;</span> <span class="br0">}</span>
    <span class="kw4">constexpr</span> <span class="kw4">auto</span> size<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span> requires sized_range<span class="sy1">&lt;</span><span class="kw4">const</span> R<span class="sy1">&gt;</span>
    <span class="br0">{</span> <span class="kw1">return</span> <a href="../ranges/size.html"><span class="kw3103">ranges::<span class="me2">size</span></span></a><span class="br0">(</span>r_<span class="br0">)</span><span class="sy4">;</span> <span class="br0">}</span>
 
    <span class="kw4">constexpr</span> <span class="kw4">auto</span> data<span class="br0">(</span><span class="br0">)</span> requires contiguous_range<span class="sy1">&lt;</span>R<span class="sy1">&gt;</span>
    <span class="br0">{</span> <span class="kw1">return</span> <a href="../../../http:/en.cppreference.com/w/cpp/ranges-ranges-placeholder/data"><span class="kw2891">ranges::<span class="me2">data</span></span></a><span class="br0">(</span>r_<span class="br0">)</span><span class="sy4">;</span> <span class="br0">}</span>
    <span class="kw4">constexpr</span> <span class="kw4">auto</span> data<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span> requires contiguous_range<span class="sy1">&lt;</span><span class="kw4">const</span> R<span class="sy1">&gt;</span>
    <span class="br0">{</span> <span class="kw1">return</span> <a href="../../../http:/en.cppreference.com/w/cpp/ranges-ranges-placeholder/data"><span class="kw2891">ranges::<span class="me2">data</span></span></a><span class="br0">(</span>r_<span class="br0">)</span><span class="sy4">;</span> <span class="br0">}</span>
  <span class="br0">}</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<h4><span class="mw-headline" id="Class_template_std::ranges::filter_view">Class template <span class="t-lc"><a href="../ranges/filter_view.html" title="cpp/ranges/filter view">std::ranges::filter_view</a></span></span></h4>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">namespace</span> std<span class="sy4">::</span><span class="me2">ranges</span> <span class="br0">{</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span>input_range V, indirect_unary_predicate<span class="sy1">&lt;</span>iterator_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;&gt;</span> Pred<span class="sy1">&gt;</span>
    requires view<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> is_object_v<span class="sy1">&lt;</span>Pred<span class="sy1">&gt;</span>
  <span class="kw1">class</span> filter_view <span class="sy4">:</span> <span class="kw1">public</span> view_interface<span class="sy1">&lt;</span>filter_view<span class="sy1">&lt;</span>V, Pred<span class="sy1">&gt;&gt;</span> <span class="br0">{</span>
  <span class="kw1">private</span><span class="sy4">:</span>
    V base_ <span class="sy1">=</span> V<span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>                              <span class="co1">// exposition only</span>
    <span class="coMULTI">/*copyable-box*/</span><span class="sy1">&lt;</span>Pred<span class="sy1">&gt;</span> pred_<span class="sy4">;</span>               <span class="co1">// exposition only</span>
 
    <span class="co1">// class filter_view::iterator</span>
    <span class="kw1">class</span> iterator<span class="sy4">;</span>                             <span class="co1">// exposition only</span>
 
    <span class="co1">// class filter_view::sentinel</span>
    <span class="kw1">class</span> sentinel<span class="sy4">;</span>                             <span class="co1">// exposition only</span>
 
  <span class="kw1">public</span><span class="sy4">:</span>
    filter_view<span class="br0">(</span><span class="br0">)</span> requires default_initializable<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
      default_initializable<span class="sy1">&lt;</span>Pred<span class="sy1">&gt;</span> <span class="sy1">=</span> <span class="kw1">default</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> filter_view<span class="br0">(</span>V base, Pred pred<span class="br0">)</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> V base<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span><span class="sy3">&amp;</span> requires copy_constructible<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> <span class="br0">{</span> <span class="kw1">return</span> base_<span class="sy4">;</span> <span class="br0">}</span>
    <span class="kw4">constexpr</span> V base<span class="br0">(</span><span class="br0">)</span> <span class="sy3">&amp;&amp;</span> <span class="br0">{</span> <span class="kw1">return</span> std<span class="sy4">::</span><span class="me2">move</span><span class="br0">(</span>base_<span class="br0">)</span><span class="sy4">;</span> <span class="br0">}</span>
 
    <span class="kw4">constexpr</span> <span class="kw4">const</span> Pred<span class="sy3">&amp;</span> pred<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> iterator begin<span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> <span class="kw4">auto</span> end<span class="br0">(</span><span class="br0">)</span> <span class="br0">{</span>
      <span class="kw1">if</span> <span class="kw4">constexpr</span> <span class="br0">(</span>common_range<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span><span class="br0">)</span>
        <span class="kw1">return</span> iterator<span class="br0">{</span><span class="sy2">*</span>this, <a href="../../../http:/en.cppreference.com/w/cpp/ranges-ranges-placeholder/end"><span class="kw2887">ranges::<span class="me2">end</span></span></a><span class="br0">(</span>base_<span class="br0">)</span><span class="br0">}</span><span class="sy4">;</span>
      <span class="kw1">else</span>
        <span class="kw1">return</span> sentinel<span class="br0">{</span><span class="sy2">*</span>this<span class="br0">}</span><span class="sy4">;</span>
    <span class="br0">}</span>
  <span class="br0">}</span><span class="sy4">;</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> R, <span class="kw1">class</span> Pred<span class="sy1">&gt;</span>
    filter_view<span class="br0">(</span>R<span class="sy3">&amp;&amp;</span>, Pred<span class="br0">)</span> <span class="sy2">-</span><span class="sy1">&gt;</span> filter_view<span class="sy1">&lt;</span><a href="../ranges/all_view.html"><span class="kw2919">views::<span class="me2">all_t</span></span></a><span class="sy1">&lt;</span>R<span class="sy1">&gt;</span>, Pred<span class="sy1">&gt;</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<h4><span class="mw-headline" id="Class_std::ranges::filter_view::iterator">Class <span class="t-lc">std::ranges::filter_view::iterator</span></span></h4>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">namespace</span> std<span class="sy4">::</span><span class="me2">ranges</span> <span class="br0">{</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span>input_range V, indirect_unary_predicate<span class="sy1">&lt;</span>iterator_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;&gt;</span> Pred<span class="sy1">&gt;</span>
    requires view<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> is_object_v<span class="sy1">&lt;</span>Pred<span class="sy1">&gt;</span>
  <span class="kw1">class</span> filter_view<span class="sy1">&lt;</span>V, Pred<span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">iterator</span> <span class="br0">{</span>
  <span class="kw1">private</span><span class="sy4">:</span>
    iterator_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> current_ <span class="sy1">=</span> iterator_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span><span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>   <span class="co1">// exposition only</span>
    filter_view<span class="sy2">*</span> parent_ <span class="sy1">=</span> nullptr<span class="sy4">;</span>             <span class="co1">// exposition only</span>
 
  <span class="kw1">public</span><span class="sy4">:</span>
    <span class="kw1">using</span> iterator_concept  <span class="sy1">=</span> <span class="coMULTI">/* see description */</span><span class="sy4">;</span>
    <span class="kw1">using</span> iterator_category <span class="sy1">=</span> <span class="coMULTI">/* see description */</span><span class="sy4">;</span>        <span class="co1">// not always present</span>
    <span class="kw1">using</span> value_type        <span class="sy1">=</span> range_value_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span><span class="sy4">;</span>
    <span class="kw1">using</span> difference_type   <span class="sy1">=</span> range_difference_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span><span class="sy4">;</span>
 
    iterator<span class="br0">(</span><span class="br0">)</span> requires default_initializable<span class="sy1">&lt;</span>iterator_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;&gt;</span> <span class="sy1">=</span> <span class="kw1">default</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> iterator<span class="br0">(</span>filter_view<span class="sy3">&amp;</span> parent, iterator_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> current<span class="br0">)</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> <span class="kw4">const</span> iterator_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span><span class="sy3">&amp;</span> base<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span> <span class="sy3">&amp;</span> <span class="kw1">noexcept</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> iterator_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> base<span class="br0">(</span><span class="br0">)</span> <span class="sy3">&amp;&amp;</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> range_reference_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> operator<span class="sy2">*</span><span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> iterator_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> operator<span class="sy2">-</span><span class="sy1">&gt;</span><span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span>
      requires <span class="coMULTI">/*has-arrow*/</span><span class="sy1">&lt;</span>iterator_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;&gt;</span> <span class="sy3">&amp;&amp;</span> copyable<span class="sy1">&lt;</span>iterator_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;&gt;</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> iterator<span class="sy3">&amp;</span> operator<span class="sy2">++</span><span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> <span class="kw4">void</span> operator<span class="sy2">++</span><span class="br0">(</span><span class="kw4">int</span><span class="br0">)</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> iterator operator<span class="sy2">++</span><span class="br0">(</span><span class="kw4">int</span><span class="br0">)</span> requires forward_range<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> iterator<span class="sy3">&amp;</span> operator<span class="sy2">--</span><span class="br0">(</span><span class="br0">)</span> requires bidirectional_range<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> iterator operator<span class="sy2">--</span><span class="br0">(</span><span class="kw4">int</span><span class="br0">)</span> requires bidirectional_range<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span><span class="sy4">;</span>
 
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> operator<span class="sy1">==</span><span class="br0">(</span><span class="kw4">const</span> iterator<span class="sy3">&amp;</span> x, <span class="kw4">const</span> iterator<span class="sy3">&amp;</span> y<span class="br0">)</span>
      requires equality_comparable<span class="sy1">&lt;</span>iterator_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;&gt;</span><span class="sy4">;</span>
 
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> range_rvalue_reference_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> iter_move<span class="br0">(</span><span class="kw4">const</span> iterator<span class="sy3">&amp;</span> i<span class="br0">)</span>
      <span class="kw1">noexcept</span><span class="br0">(</span><span class="kw1">noexcept</span><span class="br0">(</span><a href="../iterator/ranges/iter_move.html"><span class="kw3143">ranges::<span class="me2">iter_move</span></span></a><span class="br0">(</span>i.<span class="me1">current_</span><span class="br0">)</span><span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
 
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> <span class="kw4">void</span> iter_swap<span class="br0">(</span><span class="kw4">const</span> iterator<span class="sy3">&amp;</span> x, <span class="kw4">const</span> iterator<span class="sy3">&amp;</span> y<span class="br0">)</span>
      <span class="kw1">noexcept</span><span class="br0">(</span><span class="kw1">noexcept</span><span class="br0">(</span><a href="../iterator/ranges/iter_swap.html"><span class="kw3278">ranges::<span class="me2">iter_swap</span></span></a><span class="br0">(</span>x.<span class="me1">current_</span>, y.<span class="me1">current_</span><span class="br0">)</span><span class="br0">)</span><span class="br0">)</span>
      requires indirectly_swappable<span class="sy1">&lt;</span>iterator_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;&gt;</span><span class="sy4">;</span>
  <span class="br0">}</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<h4><span class="mw-headline" id="Class_std::ranges::filter_view::sentinel">Class <span class="t-lc">std::ranges::filter_view::sentinel</span></span></h4>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">namespace</span> std<span class="sy4">::</span><span class="me2">ranges</span> <span class="br0">{</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span>input_range V, indirect_unary_predicate<span class="sy1">&lt;</span>iterator_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;&gt;</span> Pred<span class="sy1">&gt;</span>
    requires view<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> is_object_v<span class="sy1">&lt;</span>Pred<span class="sy1">&gt;</span>
  <span class="kw1">class</span> filter_view<span class="sy1">&lt;</span>V, Pred<span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">sentinel</span> <span class="br0">{</span>
  <span class="kw1">private</span><span class="sy4">:</span>
    sentinel_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> end_ <span class="sy1">=</span> sentinel_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span><span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>       <span class="co1">// exposition only</span>
 
  <span class="kw1">public</span><span class="sy4">:</span>
    sentinel<span class="br0">(</span><span class="br0">)</span> <span class="sy1">=</span> <span class="kw1">default</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> <span class="kw1">explicit</span> sentinel<span class="br0">(</span>filter_view<span class="sy3">&amp;</span> parent<span class="br0">)</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> sentinel_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> base<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span><span class="sy4">;</span>
 
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> operator<span class="sy1">==</span><span class="br0">(</span><span class="kw4">const</span> iterator<span class="sy3">&amp;</span> x, <span class="kw4">const</span> sentinel<span class="sy3">&amp;</span> y<span class="br0">)</span><span class="sy4">;</span>
  <span class="br0">}</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<h4><span class="mw-headline" id="Class_template_std::ranges::transform_view">Class template <span class="t-lc"><a href="../ranges/transform_view.html" title="cpp/ranges/transform view">std::ranges::transform_view</a></span></span></h4>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">namespace</span> std<span class="sy4">::</span><span class="me2">ranges</span> <span class="br0">{</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span>input_range V, copy_constructible F<span class="sy1">&gt;</span>
    requires view<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> is_object_v<span class="sy1">&lt;</span>F<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
             regular_invocable<span class="sy1">&lt;</span>F<span class="sy3">&amp;</span>, range_reference_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;&gt;</span> <span class="sy3">&amp;&amp;</span>
             <span class="coMULTI">/*can-reference*/</span><span class="sy1">&lt;</span>invoke_result_t<span class="sy1">&lt;</span>F<span class="sy3">&amp;</span>, range_reference_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;&gt;&gt;</span>
  <span class="kw1">class</span> transform_view <span class="sy4">:</span> <span class="kw1">public</span> view_interface<span class="sy1">&lt;</span>transform_view<span class="sy1">&lt;</span>V, F<span class="sy1">&gt;&gt;</span> <span class="br0">{</span>
  <span class="kw1">private</span><span class="sy4">:</span>
    <span class="co1">// class template transform_view::iterator</span>
    <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw4">bool</span><span class="sy1">&gt;</span> <span class="kw1">struct</span> iterator<span class="sy4">;</span>             <span class="co1">// exposition only</span>
 
    <span class="co1">// class template transform_view::sentinel</span>
    <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw4">bool</span><span class="sy1">&gt;</span> <span class="kw1">struct</span> sentinel<span class="sy4">;</span>             <span class="co1">// exposition only</span>
 
    V base_ <span class="sy1">=</span> V<span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>                              <span class="co1">// exposition only</span>
    <span class="coMULTI">/*copyable-box*/</span><span class="sy1">&lt;</span>F<span class="sy1">&gt;</span> fun_<span class="sy4">;</span>                   <span class="co1">// exposition only</span>
 
  <span class="kw1">public</span><span class="sy4">:</span>
    transform_view<span class="br0">(</span><span class="br0">)</span> requires default_initializable<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
      default_initializable<span class="sy1">&lt;</span>F<span class="sy1">&gt;</span> <span class="sy1">=</span> <span class="kw1">default</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> transform_view<span class="br0">(</span>V base, F fun<span class="br0">)</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> V base<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span><span class="sy3">&amp;</span> requires copy_constructible<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> <span class="br0">{</span> <span class="kw1">return</span> base_<span class="sy4">;</span> <span class="br0">}</span>
    <span class="kw4">constexpr</span> V base<span class="br0">(</span><span class="br0">)</span> <span class="sy3">&amp;&amp;</span> <span class="br0">{</span> <span class="kw1">return</span> std<span class="sy4">::</span><span class="me2">move</span><span class="br0">(</span>base_<span class="br0">)</span><span class="sy4">;</span> <span class="br0">}</span>
 
    <span class="kw4">constexpr</span> iterator<span class="sy1">&lt;</span><span class="kw2">false</span><span class="sy1">&gt;</span> begin<span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> iterator<span class="sy1">&lt;</span><span class="kw2">true</span><span class="sy1">&gt;</span> begin<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span>
      requires range<span class="sy1">&lt;</span><span class="kw4">const</span> V<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
               regular_invocable<span class="sy1">&lt;</span><span class="kw4">const</span> F<span class="sy3">&amp;</span>, range_reference_t<span class="sy1">&lt;</span><span class="kw4">const</span> V<span class="sy1">&gt;&gt;</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> sentinel<span class="sy1">&lt;</span><span class="kw2">false</span><span class="sy1">&gt;</span> end<span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> iterator<span class="sy1">&lt;</span><span class="kw2">false</span><span class="sy1">&gt;</span> end<span class="br0">(</span><span class="br0">)</span> requires common_range<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> sentinel<span class="sy1">&lt;</span><span class="kw2">true</span><span class="sy1">&gt;</span> end<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span>
      requires range<span class="sy1">&lt;</span><span class="kw4">const</span> V<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
               regular_invocable<span class="sy1">&lt;</span><span class="kw4">const</span> F<span class="sy3">&amp;</span>, range_reference_t<span class="sy1">&lt;</span><span class="kw4">const</span> V<span class="sy1">&gt;&gt;</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> iterator<span class="sy1">&lt;</span><span class="kw2">true</span><span class="sy1">&gt;</span> end<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span>
      requires common_range<span class="sy1">&lt;</span><span class="kw4">const</span> V<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
               regular_invocable<span class="sy1">&lt;</span><span class="kw4">const</span> F<span class="sy3">&amp;</span>, range_reference_t<span class="sy1">&lt;</span><span class="kw4">const</span> V<span class="sy1">&gt;&gt;</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> <span class="kw4">auto</span> size<span class="br0">(</span><span class="br0">)</span> requires sized_range<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> <span class="br0">{</span> <span class="kw1">return</span> <a href="../ranges/size.html"><span class="kw3103">ranges::<span class="me2">size</span></span></a><span class="br0">(</span>base_<span class="br0">)</span><span class="sy4">;</span> <span class="br0">}</span>
    <span class="kw4">constexpr</span> <span class="kw4">auto</span> size<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span> requires sized_range<span class="sy1">&lt;</span><span class="kw4">const</span> V<span class="sy1">&gt;</span>
    <span class="br0">{</span> <span class="kw1">return</span> <a href="../ranges/size.html"><span class="kw3103">ranges::<span class="me2">size</span></span></a><span class="br0">(</span>base_<span class="br0">)</span><span class="sy4">;</span> <span class="br0">}</span>
  <span class="br0">}</span><span class="sy4">;</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> R, <span class="kw1">class</span> F<span class="sy1">&gt;</span>
    transform_view<span class="br0">(</span>R<span class="sy3">&amp;&amp;</span>, F<span class="br0">)</span> <span class="sy2">-</span><span class="sy1">&gt;</span> transform_view<span class="sy1">&lt;</span><a href="../ranges/all_view.html"><span class="kw2919">views::<span class="me2">all_t</span></span></a><span class="sy1">&lt;</span>R<span class="sy1">&gt;</span>, F<span class="sy1">&gt;</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<h4><span class="mw-headline" id="Class_template_std::ranges::transform_view::iterator">Class template <span class="t-lc">std::ranges::transform_view::iterator</span></span></h4>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">namespace</span> std<span class="sy4">::</span><span class="me2">ranges</span> <span class="br0">{</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span>input_range V, copy_constructible F<span class="sy1">&gt;</span>
    requires view<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> is_object_v<span class="sy1">&lt;</span>F<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
             regular_invocable<span class="sy1">&lt;</span>F<span class="sy3">&amp;</span>, range_reference_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;&gt;</span> <span class="sy3">&amp;&amp;</span>
             <span class="coMULTI">/*can-reference*/</span><span class="sy1">&lt;</span>invoke_result_t<span class="sy1">&lt;</span>F<span class="sy3">&amp;</span>, range_reference_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;&gt;&gt;</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw4">bool</span> Const<span class="sy1">&gt;</span>
  <span class="kw1">class</span> transform_view<span class="sy1">&lt;</span>V, F<span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">iterator</span> <span class="br0">{</span>
  <span class="kw1">private</span><span class="sy4">:</span>
    <span class="kw1">using</span> Parent <span class="sy1">=</span> <span class="coMULTI">/*maybe-const*/</span><span class="sy1">&lt;</span>Const, transform_view<span class="sy1">&gt;</span><span class="sy4">;</span>      <span class="co1">// exposition only</span>
    <span class="kw1">using</span> Base <span class="sy1">=</span> <span class="coMULTI">/*maybe-const*/</span><span class="sy1">&lt;</span>Const, V<span class="sy1">&gt;</span><span class="sy4">;</span>                     <span class="co1">// exposition only</span>
    iterator_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span> current_ <span class="sy1">=</span> iterator_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span><span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>             <span class="co1">// exposition only</span>
    Parent<span class="sy2">*</span> parent_ <span class="sy1">=</span> nullptr<span class="sy4">;</span>                                  <span class="co1">// exposition only</span>
 
  <span class="kw1">public</span><span class="sy4">:</span>
    <span class="kw1">using</span> iterator_concept  <span class="sy1">=</span> <span class="coMULTI">/* see description */</span><span class="sy4">;</span>
    <span class="kw1">using</span> iterator_category <span class="sy1">=</span> <span class="coMULTI">/* see description */</span><span class="sy4">;</span>            <span class="co1">// not always present</span>
    <span class="kw1">using</span> value_type        <span class="sy1">=</span>
      remove_cvref_t<span class="sy1">&lt;</span>invoke_result_t<span class="sy1">&lt;</span>F<span class="sy3">&amp;</span>, range_reference_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;&gt;&gt;</span><span class="sy4">;</span>
    <span class="kw1">using</span> difference_type   <span class="sy1">=</span> range_difference_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span><span class="sy4">;</span>
 
    iterator<span class="br0">(</span><span class="br0">)</span> requires default_initializable<span class="sy1">&lt;</span>iterator_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;&gt;</span> <span class="sy1">=</span> <span class="kw1">default</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> iterator<span class="br0">(</span>Parent<span class="sy3">&amp;</span> parent, iterator_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span> current<span class="br0">)</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> iterator<span class="br0">(</span>iterator<span class="sy1">&lt;</span><span class="sy3">!</span>Const<span class="sy1">&gt;</span> i<span class="br0">)</span>
      requires Const <span class="sy3">&amp;&amp;</span> convertible_to<span class="sy1">&lt;</span>iterator_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span>, iterator_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;&gt;</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> <span class="kw4">const</span> iterator_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span><span class="sy3">&amp;</span> base<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span> <span class="sy3">&amp;</span> <span class="kw1">noexcept</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> iterator_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span> base<span class="br0">(</span><span class="br0">)</span> <span class="sy3">&amp;&amp;</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> decltype<span class="br0">(</span><span class="kw4">auto</span><span class="br0">)</span> operator<span class="sy2">*</span><span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span> <span class="br0">{</span>
      <span class="kw1">return</span> invoke<span class="br0">(</span><span class="sy2">*</span>parent_<span class="sy2">-</span><span class="sy1">&gt;</span>fun_, <span class="sy2">*</span>current_<span class="br0">)</span><span class="sy4">;</span>
    <span class="br0">}</span>
 
    <span class="kw4">constexpr</span> iterator<span class="sy3">&amp;</span> operator<span class="sy2">++</span><span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> <span class="kw4">void</span> operator<span class="sy2">++</span><span class="br0">(</span><span class="kw4">int</span><span class="br0">)</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> iterator operator<span class="sy2">++</span><span class="br0">(</span><span class="kw4">int</span><span class="br0">)</span> requires forward_range<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> iterator<span class="sy3">&amp;</span> operator<span class="sy2">--</span><span class="br0">(</span><span class="br0">)</span> requires bidirectional_range<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> iterator operator<span class="sy2">--</span><span class="br0">(</span><span class="kw4">int</span><span class="br0">)</span> requires bidirectional_range<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> iterator<span class="sy3">&amp;</span> operator<span class="sy2">+</span><span class="sy1">=</span><span class="br0">(</span>difference_type n<span class="br0">)</span>
      requires random_access_range<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> iterator<span class="sy3">&amp;</span> operator<span class="sy2">-</span><span class="sy1">=</span><span class="br0">(</span>difference_type n<span class="br0">)</span>
      requires random_access_range<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> decltype<span class="br0">(</span><span class="kw4">auto</span><span class="br0">)</span> operator<span class="br0">[</span><span class="br0">]</span><span class="br0">(</span>difference_type n<span class="br0">)</span> <span class="kw4">const</span>
      requires random_access_range<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span> <span class="br0">{</span>
      <span class="kw1">return</span> invoke<span class="br0">(</span><span class="sy2">*</span>parent_<span class="sy2">-</span><span class="sy1">&gt;</span>fun_, current_<span class="br0">[</span>n<span class="br0">]</span><span class="br0">)</span><span class="sy4">;</span>
    <span class="br0">}</span>
 
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> operator<span class="sy1">==</span><span class="br0">(</span><span class="kw4">const</span> iterator<span class="sy3">&amp;</span> x, <span class="kw4">const</span> iterator<span class="sy3">&amp;</span> y<span class="br0">)</span>
      requires equality_comparable<span class="sy1">&lt;</span>iterator_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;&gt;</span><span class="sy4">;</span>
 
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> operator<span class="sy1">&lt;</span><span class="br0">(</span><span class="kw4">const</span> iterator<span class="sy3">&amp;</span> x, <span class="kw4">const</span> iterator<span class="sy3">&amp;</span> y<span class="br0">)</span>
      requires random_access_range<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span><span class="sy4">;</span>
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> operator<span class="sy1">&gt;</span><span class="br0">(</span><span class="kw4">const</span> iterator<span class="sy3">&amp;</span> x, <span class="kw4">const</span> iterator<span class="sy3">&amp;</span> y<span class="br0">)</span>
      requires random_access_range<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span><span class="sy4">;</span>
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> operator<span class="sy1">&lt;=</span><span class="br0">(</span><span class="kw4">const</span> iterator<span class="sy3">&amp;</span> x, <span class="kw4">const</span> iterator<span class="sy3">&amp;</span> y<span class="br0">)</span>
      requires random_access_range<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span><span class="sy4">;</span>
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> operator<span class="sy1">&gt;=</span><span class="br0">(</span><span class="kw4">const</span> iterator<span class="sy3">&amp;</span> x, <span class="kw4">const</span> iterator<span class="sy3">&amp;</span> y<span class="br0">)</span>
      requires random_access_range<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span><span class="sy4">;</span>
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> <span class="kw4">auto</span> operator<span class="sy1">&lt;=&gt;</span><span class="br0">(</span><span class="kw4">const</span> iterator<span class="sy3">&amp;</span> x, <span class="kw4">const</span> iterator<span class="sy3">&amp;</span> y<span class="br0">)</span>
      requires random_access_range<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> three_way_comparable<span class="sy1">&lt;</span>iterator_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;&gt;</span><span class="sy4">;</span>
 
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> iterator operator<span class="sy2">+</span><span class="br0">(</span>iterator i, difference_type n<span class="br0">)</span>
      requires random_access_range<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span><span class="sy4">;</span>
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> iterator operator<span class="sy2">+</span><span class="br0">(</span>difference_type n, iterator i<span class="br0">)</span>
      requires random_access_range<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span><span class="sy4">;</span>
 
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> iterator operator<span class="sy2">-</span><span class="br0">(</span>iterator i, difference_type n<span class="br0">)</span>
      requires random_access_range<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span><span class="sy4">;</span>
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> difference_type operator<span class="sy2">-</span><span class="br0">(</span><span class="kw4">const</span> iterator<span class="sy3">&amp;</span> x, <span class="kw4">const</span> iterator<span class="sy3">&amp;</span> y<span class="br0">)</span>
      requires sized_sentinel_for<span class="sy1">&lt;</span>iterator_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span>, iterator_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;&gt;</span><span class="sy4">;</span>
 
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> decltype<span class="br0">(</span><span class="kw4">auto</span><span class="br0">)</span> iter_move<span class="br0">(</span><span class="kw4">const</span> iterator<span class="sy3">&amp;</span> i<span class="br0">)</span>
      <span class="kw1">noexcept</span><span class="br0">(</span><span class="kw1">noexcept</span><span class="br0">(</span>invoke<span class="br0">(</span><span class="sy2">*</span>i.<span class="me1">parent_</span><span class="sy2">-</span><span class="sy1">&gt;</span>fun_, <span class="sy2">*</span>i.<span class="me1">current_</span><span class="br0">)</span><span class="br0">)</span><span class="br0">)</span> <span class="br0">{</span>
      <span class="kw1">if</span> <span class="kw4">constexpr</span> <span class="br0">(</span>is_lvalue_reference_v<span class="sy1">&lt;</span>decltype<span class="br0">(</span><span class="sy2">*</span>i<span class="br0">)</span><span class="sy1">&gt;</span><span class="br0">)</span>
        <span class="kw1">return</span> std<span class="sy4">::</span><span class="me2">move</span><span class="br0">(</span><span class="sy2">*</span>i<span class="br0">)</span><span class="sy4">;</span>
      <span class="kw1">else</span>
        <span class="kw1">return</span> <span class="sy2">*</span>i<span class="sy4">;</span>
    <span class="br0">}</span>
  <span class="br0">}</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<h4><span class="mw-headline" id="Class_template_std::ranges::transform_view::sentinel">Class template <span class="t-lc">std::ranges::transform_view::sentinel</span></span></h4>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">namespace</span> std<span class="sy4">::</span><span class="me2">ranges</span> <span class="br0">{</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span>input_range V, copy_constructible F<span class="sy1">&gt;</span>
    requires view<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> is_object_v<span class="sy1">&lt;</span>F<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
             regular_invocable<span class="sy1">&lt;</span>F<span class="sy3">&amp;</span>, range_reference_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;&gt;</span> <span class="sy3">&amp;&amp;</span>
             <span class="coMULTI">/*can-reference*/</span><span class="sy1">&lt;</span>invoke_result_t<span class="sy1">&lt;</span>F<span class="sy3">&amp;</span>, range_reference_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;&gt;&gt;</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw4">bool</span> Const<span class="sy1">&gt;</span>
  <span class="kw1">class</span> transform_view<span class="sy1">&lt;</span>V, F<span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">sentinel</span> <span class="br0">{</span>
  <span class="kw1">private</span><span class="sy4">:</span>
    <span class="kw1">using</span> Parent <span class="sy1">=</span> <span class="coMULTI">/*maybe-const*/</span><span class="sy1">&lt;</span>Const, transform_view<span class="sy1">&gt;</span><span class="sy4">;</span>  <span class="co1">// exposition only</span>
    <span class="kw1">using</span> Base <span class="sy1">=</span> <span class="coMULTI">/*maybe-const*/</span><span class="sy1">&lt;</span>Const, V<span class="sy1">&gt;</span><span class="sy4">;</span>                 <span class="co1">// exposition only</span>
    sentinel_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span> end_ <span class="sy1">=</span> sentinel_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span><span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>             <span class="co1">// exposition only</span>
  <span class="kw1">public</span><span class="sy4">:</span>
    sentinel<span class="br0">(</span><span class="br0">)</span> <span class="sy1">=</span> <span class="kw1">default</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> <span class="kw1">explicit</span> sentinel<span class="br0">(</span>sentinel_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span> end<span class="br0">)</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> sentinel<span class="br0">(</span>sentinel<span class="sy1">&lt;</span><span class="sy3">!</span>Const<span class="sy1">&gt;</span> i<span class="br0">)</span>
      requires Const <span class="sy3">&amp;&amp;</span> convertible_to<span class="sy1">&lt;</span>sentinel_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span>, sentinel_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;&gt;</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> sentinel_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span> base<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span><span class="sy4">;</span>
 
    <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw4">bool</span> OtherConst<span class="sy1">&gt;</span>
      requires sentinel_for<span class="sy1">&lt;</span>sentinel_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span>, iterator_t<span class="sy1">&lt;</span><span class="coMULTI">/*maybe-const*/</span><span class="sy1">&lt;</span>OtherConst, V<span class="sy1">&gt;&gt;&gt;</span>
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> operator<span class="sy1">==</span><span class="br0">(</span><span class="kw4">const</span> iterator<span class="sy1">&lt;</span>OtherConst<span class="sy1">&gt;</span><span class="sy3">&amp;</span> x, <span class="kw4">const</span> sentinel<span class="sy3">&amp;</span> y<span class="br0">)</span><span class="sy4">;</span>
 
    <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw4">bool</span> OtherConst<span class="sy1">&gt;</span>
      requires sized_sentinel_for<span class="sy1">&lt;</span>sentinel_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span>,
        iterator_t<span class="sy1">&lt;</span><span class="coMULTI">/*maybe-const*/</span><span class="sy1">&lt;</span>OtherConst, V<span class="sy1">&gt;&gt;&gt;</span>
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> range_difference_t<span class="sy1">&lt;</span><span class="coMULTI">/*maybe-const*/</span><span class="sy1">&lt;</span>OtherConst, V<span class="sy1">&gt;&gt;</span>
      operator<span class="sy2">-</span><span class="br0">(</span><span class="kw4">const</span> iterator<span class="sy1">&lt;</span>OtherConst<span class="sy1">&gt;</span><span class="sy3">&amp;</span> x, <span class="kw4">const</span> sentinel<span class="sy3">&amp;</span> y<span class="br0">)</span><span class="sy4">;</span>
 
    <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw4">bool</span> OtherConst<span class="sy1">&gt;</span>
      requires sized_sentinel_for<span class="sy1">&lt;</span>sentinel_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span>,
        iterator_t<span class="sy1">&lt;</span><span class="coMULTI">/*maybe-const*/</span><span class="sy1">&lt;</span>OtherConst, V<span class="sy1">&gt;&gt;&gt;</span>
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> range_difference_t<span class="sy1">&lt;</span><span class="coMULTI">/*maybe-const*/</span><span class="sy1">&lt;</span>OtherConst, V<span class="sy1">&gt;&gt;</span>
      operator<span class="sy2">-</span><span class="br0">(</span><span class="kw4">const</span> sentinel<span class="sy3">&amp;</span> y, <span class="kw4">const</span> iterator<span class="sy1">&lt;</span>OtherConst<span class="sy1">&gt;</span><span class="sy3">&amp;</span> x<span class="br0">)</span><span class="sy4">;</span>
  <span class="br0">}</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<h4><span class="mw-headline" id="Class_template_std::ranges::take_view">Class template <span class="t-lc"><a href="../ranges/take_view.html" title="cpp/ranges/take view">std::ranges::take_view</a></span></span></h4>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">namespace</span> std<span class="sy4">::</span><span class="me2">ranges</span> <span class="br0">{</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span>view V<span class="sy1">&gt;</span>
  <span class="kw1">class</span> take_view <span class="sy4">:</span> <span class="kw1">public</span> view_interface<span class="sy1">&lt;</span>take_view<span class="sy1">&lt;</span>V<span class="sy1">&gt;&gt;</span> <span class="br0">{</span>
  <span class="kw1">private</span><span class="sy4">:</span>
    V base_ <span class="sy1">=</span> V<span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>                                      <span class="co1">// exposition only</span>
    range_difference_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> count_ <span class="sy1">=</span> <span class="nu0">0</span><span class="sy4">;</span>                   <span class="co1">// exposition only</span>
 
    <span class="co1">// class template take_view::sentinel</span>
    <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw4">bool</span><span class="sy1">&gt;</span> <span class="kw1">struct</span> sentinel<span class="sy4">;</span>                     <span class="co1">// exposition only</span>
 
  <span class="kw1">public</span><span class="sy4">:</span>
    take_view<span class="br0">(</span><span class="br0">)</span> requires default_initializable<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> <span class="sy1">=</span> <span class="kw1">default</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> take_view<span class="br0">(</span>V base, range_difference_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> count<span class="br0">)</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> V base<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span><span class="sy3">&amp;</span> requires copy_constructible<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> <span class="br0">{</span> <span class="kw1">return</span> base_<span class="sy4">;</span> <span class="br0">}</span>
    <span class="kw4">constexpr</span> V base<span class="br0">(</span><span class="br0">)</span> <span class="sy3">&amp;&amp;</span> <span class="br0">{</span> <span class="kw1">return</span> std<span class="sy4">::</span><span class="me2">move</span><span class="br0">(</span>base_<span class="br0">)</span><span class="sy4">;</span> <span class="br0">}</span>
 
    <span class="kw4">constexpr</span> <span class="kw4">auto</span> begin<span class="br0">(</span><span class="br0">)</span> requires <span class="br0">(</span><span class="sy3">!</span><span class="coMULTI">/*simple-view*/</span><span class="sy1">&lt;</span>V<span class="sy1">&gt;</span><span class="br0">)</span> <span class="br0">{</span>
      <span class="kw1">if</span> <span class="kw4">constexpr</span> <span class="br0">(</span>sized_range<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span><span class="br0">)</span> <span class="br0">{</span>
        <span class="kw1">if</span> <span class="kw4">constexpr</span> <span class="br0">(</span>random_access_range<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span><span class="br0">)</span> <span class="br0">{</span>
          <span class="kw1">return</span> <a href="../../../http:/en.cppreference.com/w/cpp/ranges-ranges-placeholder/begin"><span class="kw2885">ranges::<span class="me2">begin</span></span></a><span class="br0">(</span>base_<span class="br0">)</span><span class="sy4">;</span>
        <span class="br0">}</span> <span class="kw1">else</span> <span class="br0">{</span>
          <span class="kw4">auto</span> sz <span class="sy1">=</span> range_difference_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span><span class="br0">(</span>size<span class="br0">(</span><span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
          <span class="kw1">return</span> counted_iterator<span class="br0">(</span><a href="../../../http:/en.cppreference.com/w/cpp/ranges-ranges-placeholder/begin"><span class="kw2885">ranges::<span class="me2">begin</span></span></a><span class="br0">(</span>base_<span class="br0">)</span>, sz<span class="br0">)</span><span class="sy4">;</span>
        <span class="br0">}</span>
      <span class="br0">}</span> <span class="kw1">else</span> <span class="br0">{</span>
        <span class="kw1">return</span> counted_iterator<span class="br0">(</span><a href="../../../http:/en.cppreference.com/w/cpp/ranges-ranges-placeholder/begin"><span class="kw2885">ranges::<span class="me2">begin</span></span></a><span class="br0">(</span>base_<span class="br0">)</span>, count_<span class="br0">)</span><span class="sy4">;</span>
      <span class="br0">}</span>
    <span class="br0">}</span>
 
    <span class="kw4">constexpr</span> <span class="kw4">auto</span> begin<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span> requires range<span class="sy1">&lt;</span><span class="kw4">const</span> V<span class="sy1">&gt;</span> <span class="br0">{</span>
      <span class="kw1">if</span> <span class="kw4">constexpr</span> <span class="br0">(</span>sized_range<span class="sy1">&lt;</span><span class="kw4">const</span> V<span class="sy1">&gt;</span><span class="br0">)</span> <span class="br0">{</span>
        <span class="kw1">if</span> <span class="kw4">constexpr</span> <span class="br0">(</span>random_access_range<span class="sy1">&lt;</span><span class="kw4">const</span> V<span class="sy1">&gt;</span><span class="br0">)</span> <span class="br0">{</span>
          <span class="kw1">return</span> <a href="../../../http:/en.cppreference.com/w/cpp/ranges-ranges-placeholder/begin"><span class="kw2885">ranges::<span class="me2">begin</span></span></a><span class="br0">(</span>base_<span class="br0">)</span><span class="sy4">;</span>
        <span class="br0">}</span> <span class="kw1">else</span> <span class="br0">{</span>
          <span class="kw4">auto</span> sz <span class="sy1">=</span> range_difference_t<span class="sy1">&lt;</span><span class="kw4">const</span> V<span class="sy1">&gt;</span><span class="br0">(</span>size<span class="br0">(</span><span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
          <span class="kw1">return</span> counted_iterator<span class="br0">(</span><a href="../../../http:/en.cppreference.com/w/cpp/ranges-ranges-placeholder/begin"><span class="kw2885">ranges::<span class="me2">begin</span></span></a><span class="br0">(</span>base_<span class="br0">)</span>, sz<span class="br0">)</span><span class="sy4">;</span>
        <span class="br0">}</span>
      <span class="br0">}</span> <span class="kw1">else</span> <span class="br0">{</span>
        <span class="kw1">return</span> counted_iterator<span class="br0">(</span><a href="../../../http:/en.cppreference.com/w/cpp/ranges-ranges-placeholder/begin"><span class="kw2885">ranges::<span class="me2">begin</span></span></a><span class="br0">(</span>base_<span class="br0">)</span>, count_<span class="br0">)</span><span class="sy4">;</span>
      <span class="br0">}</span>
    <span class="br0">}</span>
 
    <span class="kw4">constexpr</span> <span class="kw4">auto</span> end<span class="br0">(</span><span class="br0">)</span> requires <span class="br0">(</span><span class="sy3">!</span><span class="coMULTI">/*simple-view*/</span><span class="sy1">&lt;</span>V<span class="sy1">&gt;</span><span class="br0">)</span> <span class="br0">{</span>
      <span class="kw1">if</span> <span class="kw4">constexpr</span> <span class="br0">(</span>sized_range<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span><span class="br0">)</span> <span class="br0">{</span>
        <span class="kw1">if</span> <span class="kw4">constexpr</span> <span class="br0">(</span>random_access_range<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span><span class="br0">)</span>
          <span class="kw1">return</span> <a href="../../../http:/en.cppreference.com/w/cpp/ranges-ranges-placeholder/begin"><span class="kw2885">ranges::<span class="me2">begin</span></span></a><span class="br0">(</span>base_<span class="br0">)</span> <span class="sy2">+</span> range_difference_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span><span class="br0">(</span>size<span class="br0">(</span><span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
        <span class="kw1">else</span>
          <span class="kw1">return</span> default_sentinel<span class="sy4">;</span>
      <span class="br0">}</span> <span class="kw1">else</span> <span class="br0">{</span>
        <span class="kw1">return</span> sentinel<span class="sy1">&lt;</span><span class="kw2">false</span><span class="sy1">&gt;</span><span class="br0">{</span><a href="../../../http:/en.cppreference.com/w/cpp/ranges-ranges-placeholder/end"><span class="kw2887">ranges::<span class="me2">end</span></span></a><span class="br0">(</span>base_<span class="br0">)</span><span class="br0">}</span><span class="sy4">;</span>
      <span class="br0">}</span>
    <span class="br0">}</span>
 
    <span class="kw4">constexpr</span> <span class="kw4">auto</span> end<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span> requires range<span class="sy1">&lt;</span><span class="kw4">const</span> V<span class="sy1">&gt;</span> <span class="br0">{</span>
      <span class="kw1">if</span> <span class="kw4">constexpr</span> <span class="br0">(</span>sized_range<span class="sy1">&lt;</span><span class="kw4">const</span> V<span class="sy1">&gt;</span><span class="br0">)</span> <span class="br0">{</span>
        <span class="kw1">if</span> <span class="kw4">constexpr</span> <span class="br0">(</span>random_access_range<span class="sy1">&lt;</span><span class="kw4">const</span> V<span class="sy1">&gt;</span><span class="br0">)</span>
          <span class="kw1">return</span> <a href="../../../http:/en.cppreference.com/w/cpp/ranges-ranges-placeholder/begin"><span class="kw2885">ranges::<span class="me2">begin</span></span></a><span class="br0">(</span>base_<span class="br0">)</span> <span class="sy2">+</span> range_difference_t<span class="sy1">&lt;</span><span class="kw4">const</span> V<span class="sy1">&gt;</span><span class="br0">(</span>size<span class="br0">(</span><span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
        <span class="kw1">else</span>
          <span class="kw1">return</span> default_sentinel<span class="sy4">;</span>
      <span class="br0">}</span> <span class="kw1">else</span> <span class="br0">{</span>
        <span class="kw1">return</span> sentinel<span class="sy1">&lt;</span><span class="kw2">true</span><span class="sy1">&gt;</span><span class="br0">{</span><a href="../../../http:/en.cppreference.com/w/cpp/ranges-ranges-placeholder/end"><span class="kw2887">ranges::<span class="me2">end</span></span></a><span class="br0">(</span>base_<span class="br0">)</span><span class="br0">}</span><span class="sy4">;</span>
      <span class="br0">}</span>
    <span class="br0">}</span>
 
    <span class="kw4">constexpr</span> <span class="kw4">auto</span> size<span class="br0">(</span><span class="br0">)</span> requires sized_range<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> <span class="br0">{</span>
      <span class="kw4">auto</span> n <span class="sy1">=</span> <a href="../ranges/size.html"><span class="kw3103">ranges::<span class="me2">size</span></span></a><span class="br0">(</span>base_<span class="br0">)</span><span class="sy4">;</span>
      <span class="kw1">return</span> <a href="../algorithm/ranges/min.html"><span class="kw3013">ranges::<span class="me2">min</span></span></a><span class="br0">(</span>n, <span class="kw1">static_cast</span><span class="sy1">&lt;</span>decltype<span class="br0">(</span>n<span class="br0">)</span><span class="sy1">&gt;</span><span class="br0">(</span>count_<span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
    <span class="br0">}</span>
 
    <span class="kw4">constexpr</span> <span class="kw4">auto</span> size<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span> requires sized_range<span class="sy1">&lt;</span><span class="kw4">const</span> V<span class="sy1">&gt;</span> <span class="br0">{</span>
      <span class="kw4">auto</span> n <span class="sy1">=</span> <a href="../ranges/size.html"><span class="kw3103">ranges::<span class="me2">size</span></span></a><span class="br0">(</span>base_<span class="br0">)</span><span class="sy4">;</span>
      <span class="kw1">return</span> <a href="../algorithm/ranges/min.html"><span class="kw3013">ranges::<span class="me2">min</span></span></a><span class="br0">(</span>n, <span class="kw1">static_cast</span><span class="sy1">&lt;</span>decltype<span class="br0">(</span>n<span class="br0">)</span><span class="sy1">&gt;</span><span class="br0">(</span>count_<span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
    <span class="br0">}</span>
  <span class="br0">}</span><span class="sy4">;</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> R<span class="sy1">&gt;</span>
    take_view<span class="br0">(</span>R<span class="sy3">&amp;&amp;</span>, range_difference_t<span class="sy1">&lt;</span>R<span class="sy1">&gt;</span><span class="br0">)</span>
      <span class="sy2">-</span><span class="sy1">&gt;</span> take_view<span class="sy1">&lt;</span><a href="../ranges/all_view.html"><span class="kw2919">views::<span class="me2">all_t</span></span></a><span class="sy1">&lt;</span>R<span class="sy1">&gt;&gt;</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<h4><span class="mw-headline" id="Class_template_std::ranges::take_view::sentinel">Class template <span class="t-lc">std::ranges::take_view::sentinel</span></span></h4>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">namespace</span> std<span class="sy4">::</span><span class="me2">ranges</span> <span class="br0">{</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span>view V<span class="sy1">&gt;</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw4">bool</span> Const<span class="sy1">&gt;</span>
  <span class="kw1">class</span> take_view<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">sentinel</span> <span class="br0">{</span>
  <span class="kw1">private</span><span class="sy4">:</span>
    <span class="kw1">using</span> Base <span class="sy1">=</span> <span class="coMULTI">/*maybe-const*/</span><span class="sy1">&lt;</span>Const, V<span class="sy1">&gt;</span><span class="sy4">;</span>                            <span class="co1">// exposition only</span>
    <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw4">bool</span> OtherConst<span class="sy1">&gt;</span>
      <span class="kw1">using</span> CI <span class="sy1">=</span>
        counted_iterator<span class="sy1">&lt;</span>iterator_t<span class="sy1">&lt;</span><span class="coMULTI">/*maybe-const*/</span><span class="sy1">&lt;</span>OtherConst, V<span class="sy1">&gt;&gt;&gt;</span><span class="sy4">;</span>  <span class="co1">// exposition only</span>
    sentinel_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span> end_ <span class="sy1">=</span> sentinel_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span><span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>                        <span class="co1">// exposition only</span>
  <span class="kw1">public</span><span class="sy4">:</span>
    sentinel<span class="br0">(</span><span class="br0">)</span> <span class="sy1">=</span> <span class="kw1">default</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> <span class="kw1">explicit</span> sentinel<span class="br0">(</span>sentinel_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span> end<span class="br0">)</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> sentinel<span class="br0">(</span>sentinel<span class="sy1">&lt;</span><span class="sy3">!</span>Const<span class="sy1">&gt;</span> s<span class="br0">)</span>
      requires Const <span class="sy3">&amp;&amp;</span> convertible_to<span class="sy1">&lt;</span>sentinel_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span>, sentinel_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;&gt;</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> sentinel_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span> base<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span><span class="sy4">;</span>
 
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> operator<span class="sy1">==</span><span class="br0">(</span><span class="kw4">const</span> CI<span class="sy1">&lt;</span>Const<span class="sy1">&gt;</span><span class="sy3">&amp;</span> y, <span class="kw4">const</span> sentinel<span class="sy3">&amp;</span> x<span class="br0">)</span><span class="sy4">;</span>
 
    <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw4">bool</span> OtherConst <span class="sy1">=</span> <span class="sy3">!</span>Const<span class="sy1">&gt;</span>
      requires sentinel_for<span class="sy1">&lt;</span>sentinel_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span>, iterator_t<span class="sy1">&lt;</span><span class="coMULTI">/*maybe-const*/</span><span class="sy1">&lt;</span>OtherConst, V<span class="sy1">&gt;&gt;&gt;</span>
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> operator<span class="sy1">==</span><span class="br0">(</span><span class="kw4">const</span> CI<span class="sy1">&lt;</span>OtherConst<span class="sy1">&gt;</span><span class="sy3">&amp;</span> y, <span class="kw4">const</span> sentinel<span class="sy3">&amp;</span> x<span class="br0">)</span><span class="sy4">;</span>
  <span class="br0">}</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<h4><span class="mw-headline" id="Class_template_std::ranges::take_while_view">Class template <span class="t-lc"><a href="../ranges/take_while_view.html" title="cpp/ranges/take while view">std::ranges::take_while_view</a></span></span></h4>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">namespace</span> std<span class="sy4">::</span><span class="me2">ranges</span> <span class="br0">{</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span>view V, <span class="kw1">class</span> Pred<span class="sy1">&gt;</span>
    requires input_range<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> is_object_v<span class="sy1">&lt;</span>Pred<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
             indirect_unary_predicate<span class="sy1">&lt;</span><span class="kw4">const</span> Pred, iterator_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;&gt;</span>
  <span class="kw1">class</span> take_while_view <span class="sy4">:</span> <span class="kw1">public</span> view_interface<span class="sy1">&lt;</span>take_while_view<span class="sy1">&lt;</span>V, Pred<span class="sy1">&gt;&gt;</span> <span class="br0">{</span>
    <span class="co1">// class template take_while_view::sentinel</span>
    <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw4">bool</span><span class="sy1">&gt;</span> <span class="kw1">class</span> sentinel<span class="sy4">;</span>                      <span class="co1">// exposition only</span>
 
    V base_ <span class="sy1">=</span> V<span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>                                      <span class="co1">// exposition only</span>
    <span class="coMULTI">/*copyable-box*/</span><span class="sy1">&lt;</span>Pred<span class="sy1">&gt;</span> pred_<span class="sy4">;</span>                       <span class="co1">// exposition only</span>
 
  <span class="kw1">public</span><span class="sy4">:</span>
    take_while_view<span class="br0">(</span><span class="br0">)</span> requires default_initializable<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
      default_initializable<span class="sy1">&lt;</span>Pred<span class="sy1">&gt;</span> <span class="sy1">=</span> <span class="kw1">default</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> take_while_view<span class="br0">(</span>V base, Pred pred<span class="br0">)</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> V base<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span><span class="sy3">&amp;</span> requires copy_constructible<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> <span class="br0">{</span> <span class="kw1">return</span> base_<span class="sy4">;</span> <span class="br0">}</span>
    <span class="kw4">constexpr</span> V base<span class="br0">(</span><span class="br0">)</span> <span class="sy3">&amp;&amp;</span> <span class="br0">{</span> <span class="kw1">return</span> std<span class="sy4">::</span><span class="me2">move</span><span class="br0">(</span>base_<span class="br0">)</span><span class="sy4">;</span> <span class="br0">}</span>
 
    <span class="kw4">constexpr</span> <span class="kw4">const</span> Pred<span class="sy3">&amp;</span> pred<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> <span class="kw4">auto</span> begin<span class="br0">(</span><span class="br0">)</span> requires <span class="br0">(</span><span class="sy3">!</span><span class="coMULTI">/*simple-view*/</span><span class="sy1">&lt;</span>V<span class="sy1">&gt;</span><span class="br0">)</span>
    <span class="br0">{</span> <span class="kw1">return</span> <a href="../../../http:/en.cppreference.com/w/cpp/ranges-ranges-placeholder/begin"><span class="kw2885">ranges::<span class="me2">begin</span></span></a><span class="br0">(</span>base_<span class="br0">)</span><span class="sy4">;</span> <span class="br0">}</span>
 
    <span class="kw4">constexpr</span> <span class="kw4">auto</span> begin<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span>
      requires range<span class="sy1">&lt;</span><span class="kw4">const</span> V<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
               indirect_unary_predicate<span class="sy1">&lt;</span><span class="kw4">const</span> Pred, iterator_t<span class="sy1">&lt;</span><span class="kw4">const</span> V<span class="sy1">&gt;&gt;</span>
    <span class="br0">{</span> <span class="kw1">return</span> <a href="../../../http:/en.cppreference.com/w/cpp/ranges-ranges-placeholder/begin"><span class="kw2885">ranges::<span class="me2">begin</span></span></a><span class="br0">(</span>base_<span class="br0">)</span><span class="sy4">;</span> <span class="br0">}</span>
 
    <span class="kw4">constexpr</span> <span class="kw4">auto</span> end<span class="br0">(</span><span class="br0">)</span> requires <span class="br0">(</span><span class="sy3">!</span><span class="coMULTI">/*simple-view*/</span><span class="sy1">&lt;</span>V<span class="sy1">&gt;</span><span class="br0">)</span>
    <span class="br0">{</span> <span class="kw1">return</span> sentinel<span class="sy1">&lt;</span><span class="kw2">false</span><span class="sy1">&gt;</span><span class="br0">(</span><a href="../../../http:/en.cppreference.com/w/cpp/ranges-ranges-placeholder/end"><span class="kw2887">ranges::<span class="me2">end</span></span></a><span class="br0">(</span>base_<span class="br0">)</span>, addressof<span class="br0">(</span><span class="sy2">*</span>pred_<span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span> <span class="br0">}</span>
 
    <span class="kw4">constexpr</span> <span class="kw4">auto</span> end<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span>
      requires range<span class="sy1">&lt;</span><span class="kw4">const</span> V<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
               indirect_unary_predicate<span class="sy1">&lt;</span><span class="kw4">const</span> Pred, iterator_t<span class="sy1">&lt;</span><span class="kw4">const</span> V<span class="sy1">&gt;&gt;</span>
    <span class="br0">{</span> <span class="kw1">return</span> sentinel<span class="sy1">&lt;</span><span class="kw2">true</span><span class="sy1">&gt;</span><span class="br0">(</span><a href="../../../http:/en.cppreference.com/w/cpp/ranges-ranges-placeholder/end"><span class="kw2887">ranges::<span class="me2">end</span></span></a><span class="br0">(</span>base_<span class="br0">)</span>, addressof<span class="br0">(</span><span class="sy2">*</span>pred_<span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span> <span class="br0">}</span>
  <span class="br0">}</span><span class="sy4">;</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> R, <span class="kw1">class</span> Pred<span class="sy1">&gt;</span>
    take_while_view<span class="br0">(</span>R<span class="sy3">&amp;&amp;</span>, Pred<span class="br0">)</span> <span class="sy2">-</span><span class="sy1">&gt;</span> take_while_view<span class="sy1">&lt;</span><a href="../ranges/all_view.html"><span class="kw2919">views::<span class="me2">all_t</span></span></a><span class="sy1">&lt;</span>R<span class="sy1">&gt;</span>, Pred<span class="sy1">&gt;</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<h4><span class="mw-headline" id="Class_template_std::ranges::take_while_view::sentinel">Class template <span class="t-lc">std::ranges::take_while_view::sentinel</span></span></h4>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">namespace</span> std<span class="sy4">::</span><span class="me2">ranges</span> <span class="br0">{</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span>view V, <span class="kw1">class</span> Pred<span class="sy1">&gt;</span>
    requires input_range<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> is_object_v<span class="sy1">&lt;</span>Pred<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
             indirect_unary_predicate<span class="sy1">&lt;</span><span class="kw4">const</span> Pred, iterator_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;&gt;</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw4">bool</span> Const<span class="sy1">&gt;</span>
  <span class="kw1">class</span> take_while_view<span class="sy1">&lt;</span>V, Pred<span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">sentinel</span> <span class="br0">{</span>
    <span class="kw1">using</span> Base <span class="sy1">=</span> <span class="coMULTI">/*maybe-const*/</span><span class="sy1">&lt;</span>Const, V<span class="sy1">&gt;</span><span class="sy4">;</span>             <span class="co1">// exposition only</span>
 
    sentinel_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span> end_ <span class="sy1">=</span> sentinel_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span><span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>         <span class="co1">// exposition only</span>
    <span class="kw4">const</span> Pred<span class="sy2">*</span> pred_ <span class="sy1">=</span> nullptr<span class="sy4">;</span>                        <span class="co1">// exposition only</span>
 
  <span class="kw1">public</span><span class="sy4">:</span>
    sentinel<span class="br0">(</span><span class="br0">)</span> <span class="sy1">=</span> <span class="kw1">default</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> <span class="kw1">explicit</span> sentinel<span class="br0">(</span>sentinel_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span> end, <span class="kw4">const</span> Pred<span class="sy2">*</span> pred<span class="br0">)</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> sentinel<span class="br0">(</span>sentinel<span class="sy1">&lt;</span><span class="sy3">!</span>Const<span class="sy1">&gt;</span> s<span class="br0">)</span>
      requires Const <span class="sy3">&amp;&amp;</span> convertible_to<span class="sy1">&lt;</span>sentinel_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span>, sentinel_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;&gt;</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> sentinel_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span> base<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span> <span class="br0">{</span> <span class="kw1">return</span> end_<span class="sy4">;</span> <span class="br0">}</span>
 
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> operator<span class="sy1">==</span><span class="br0">(</span><span class="kw4">const</span> iterator_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span><span class="sy3">&amp;</span> x, <span class="kw4">const</span> sentinel<span class="sy3">&amp;</span> y<span class="br0">)</span><span class="sy4">;</span>
 
    <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw4">bool</span> OtherConst <span class="sy1">=</span> <span class="sy3">!</span>Const<span class="sy1">&gt;</span>
      requires sentinel_for<span class="sy1">&lt;</span>sentinel_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span>, iterator_t<span class="sy1">&lt;</span><span class="coMULTI">/*maybe-const*/</span><span class="sy1">&lt;</span>OtherConst, V<span class="sy1">&gt;&gt;&gt;</span>
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> operator<span class="sy1">==</span><span class="br0">(</span><span class="kw4">const</span> iterator_t<span class="sy1">&lt;</span><span class="coMULTI">/*maybe-const*/</span><span class="sy1">&lt;</span>OtherConst, V<span class="sy1">&gt;&gt;</span><span class="sy3">&amp;</span> x,
                                     <span class="kw4">const</span> sentinel<span class="sy3">&amp;</span> y<span class="br0">)</span><span class="sy4">;</span>
  <span class="br0">}</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<h4><span class="mw-headline" id="Class_template_std::ranges::drop_view">Class template <span class="t-lc"><a href="../ranges/drop_view.html" title="cpp/ranges/drop view">std::ranges::drop_view</a></span></span></h4>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">namespace</span> std<span class="sy4">::</span><span class="me2">ranges</span> <span class="br0">{</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span>view V<span class="sy1">&gt;</span>
  <span class="kw1">class</span> drop_view <span class="sy4">:</span> <span class="kw1">public</span> view_interface<span class="sy1">&lt;</span>drop_view<span class="sy1">&lt;</span>V<span class="sy1">&gt;&gt;</span> <span class="br0">{</span>
  <span class="kw1">public</span><span class="sy4">:</span>
    drop_view<span class="br0">(</span><span class="br0">)</span> requires default_initializable<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> <span class="sy1">=</span> <span class="kw1">default</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> drop_view<span class="br0">(</span>V base, range_difference_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> count<span class="br0">)</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> V base<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span><span class="sy3">&amp;</span> requires copy_constructible<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> <span class="br0">{</span> <span class="kw1">return</span> base_<span class="sy4">;</span> <span class="br0">}</span>
    <span class="kw4">constexpr</span> V base<span class="br0">(</span><span class="br0">)</span> <span class="sy3">&amp;&amp;</span> <span class="br0">{</span> <span class="kw1">return</span> std<span class="sy4">::</span><span class="me2">move</span><span class="br0">(</span>base_<span class="br0">)</span><span class="sy4">;</span> <span class="br0">}</span>
 
    <span class="kw4">constexpr</span> <span class="kw4">auto</span> begin<span class="br0">(</span><span class="br0">)</span>
      requires <span class="br0">(</span><span class="sy3">!</span><span class="br0">(</span><span class="coMULTI">/*simple-view*/</span><span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
                  random_access_range<span class="sy1">&lt;</span><span class="kw4">const</span> V<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> sized_range<span class="sy1">&lt;</span><span class="kw4">const</span> V<span class="sy1">&gt;</span><span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> <span class="kw4">auto</span> begin<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span>
      requires random_access_range<span class="sy1">&lt;</span><span class="kw4">const</span> V<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> sized_range<span class="sy1">&lt;</span><span class="kw4">const</span> V<span class="sy1">&gt;</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> <span class="kw4">auto</span> end<span class="br0">(</span><span class="br0">)</span> requires <span class="br0">(</span><span class="sy3">!</span><span class="coMULTI">/*simple-view*/</span><span class="sy1">&lt;</span>V<span class="sy1">&gt;</span><span class="br0">)</span>
    <span class="br0">{</span> <span class="kw1">return</span> <a href="../../../http:/en.cppreference.com/w/cpp/ranges-ranges-placeholder/end"><span class="kw2887">ranges::<span class="me2">end</span></span></a><span class="br0">(</span>base_<span class="br0">)</span><span class="sy4">;</span> <span class="br0">}</span>
 
    <span class="kw4">constexpr</span> <span class="kw4">auto</span> end<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span> requires range<span class="sy1">&lt;</span><span class="kw4">const</span> V<span class="sy1">&gt;</span>
    <span class="br0">{</span> <span class="kw1">return</span> <a href="../../../http:/en.cppreference.com/w/cpp/ranges-ranges-placeholder/end"><span class="kw2887">ranges::<span class="me2">end</span></span></a><span class="br0">(</span>base_<span class="br0">)</span><span class="sy4">;</span> <span class="br0">}</span>
 
    <span class="kw4">constexpr</span> <span class="kw4">auto</span> size<span class="br0">(</span><span class="br0">)</span> requires sized_range<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> <span class="br0">{</span>
      <span class="kw4">const</span> <span class="kw4">auto</span> s <span class="sy1">=</span> <a href="../ranges/size.html"><span class="kw3103">ranges::<span class="me2">size</span></span></a><span class="br0">(</span>base_<span class="br0">)</span><span class="sy4">;</span>
      <span class="kw4">const</span> <span class="kw4">auto</span> c <span class="sy1">=</span> <span class="kw1">static_cast</span><span class="sy1">&lt;</span>decltype<span class="br0">(</span>s<span class="br0">)</span><span class="sy1">&gt;</span><span class="br0">(</span>count_<span class="br0">)</span><span class="sy4">;</span>
      <span class="kw1">return</span> s <span class="sy1">&lt;</span> c <span class="sy4">?</span> <span class="nu0">0</span> <span class="sy4">:</span> s <span class="sy2">-</span> c<span class="sy4">;</span>
    <span class="br0">}</span>
 
    <span class="kw4">constexpr</span> <span class="kw4">auto</span> size<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span> requires sized_range<span class="sy1">&lt;</span><span class="kw4">const</span> V<span class="sy1">&gt;</span> <span class="br0">{</span>
      <span class="kw4">const</span> <span class="kw4">auto</span> s <span class="sy1">=</span> <a href="../ranges/size.html"><span class="kw3103">ranges::<span class="me2">size</span></span></a><span class="br0">(</span>base_<span class="br0">)</span><span class="sy4">;</span>
      <span class="kw4">const</span> <span class="kw4">auto</span> c <span class="sy1">=</span> <span class="kw1">static_cast</span><span class="sy1">&lt;</span>decltype<span class="br0">(</span>s<span class="br0">)</span><span class="sy1">&gt;</span><span class="br0">(</span>count_<span class="br0">)</span><span class="sy4">;</span>
      <span class="kw1">return</span> s <span class="sy1">&lt;</span> c <span class="sy4">?</span> <span class="nu0">0</span> <span class="sy4">:</span> s <span class="sy2">-</span> c<span class="sy4">;</span>
    <span class="br0">}</span>
 
  <span class="kw1">private</span><span class="sy4">:</span>
    V base_ <span class="sy1">=</span> V<span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>                              <span class="co1">// exposition only</span>
    range_difference_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> count_ <span class="sy1">=</span> <span class="nu0">0</span><span class="sy4">;</span>           <span class="co1">// exposition only</span>
  <span class="br0">}</span><span class="sy4">;</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> R<span class="sy1">&gt;</span>
    drop_view<span class="br0">(</span>R<span class="sy3">&amp;&amp;</span>, range_difference_t<span class="sy1">&lt;</span>R<span class="sy1">&gt;</span><span class="br0">)</span> <span class="sy2">-</span><span class="sy1">&gt;</span> drop_view<span class="sy1">&lt;</span><a href="../ranges/all_view.html"><span class="kw2919">views::<span class="me2">all_t</span></span></a><span class="sy1">&lt;</span>R<span class="sy1">&gt;&gt;</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<h4><span class="mw-headline" id="Class_template_std::ranges::drop_while_view">Class template <span class="t-lc"><a href="../ranges/drop_while_view.html" title="cpp/ranges/drop while view">std::ranges::drop_while_view</a></span></span></h4>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">namespace</span> std<span class="sy4">::</span><span class="me2">ranges</span> <span class="br0">{</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span>view V, <span class="kw1">class</span> Pred<span class="sy1">&gt;</span>
    requires input_range<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> is_object_v<span class="sy1">&lt;</span>Pred<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
             indirect_unary_predicate<span class="sy1">&lt;</span><span class="kw4">const</span> Pred, iterator_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;&gt;</span>
  <span class="kw1">class</span> drop_while_view <span class="sy4">:</span> <span class="kw1">public</span> view_interface<span class="sy1">&lt;</span>drop_while_view<span class="sy1">&lt;</span>V, Pred<span class="sy1">&gt;&gt;</span> <span class="br0">{</span>
  <span class="kw1">public</span><span class="sy4">:</span>
    drop_while_view<span class="br0">(</span><span class="br0">)</span> requires default_initializable<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
      default_initializable<span class="sy1">&lt;</span>Pred<span class="sy1">&gt;</span> <span class="sy1">=</span> <span class="kw1">default</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> drop_while_view<span class="br0">(</span>V base, Pred pred<span class="br0">)</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> V base<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span><span class="sy3">&amp;</span> requires copy_constructible<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> <span class="br0">{</span> <span class="kw1">return</span> base_<span class="sy4">;</span> <span class="br0">}</span>
    <span class="kw4">constexpr</span> V base<span class="br0">(</span><span class="br0">)</span> <span class="sy3">&amp;&amp;</span> <span class="br0">{</span> <span class="kw1">return</span> std<span class="sy4">::</span><span class="me2">move</span><span class="br0">(</span>base_<span class="br0">)</span><span class="sy4">;</span> <span class="br0">}</span>
 
    <span class="kw4">constexpr</span> <span class="kw4">const</span> Pred<span class="sy3">&amp;</span> pred<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> <span class="kw4">auto</span> begin<span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> <span class="kw4">auto</span> end<span class="br0">(</span><span class="br0">)</span> <span class="br0">{</span> <span class="kw1">return</span> <a href="../../../http:/en.cppreference.com/w/cpp/ranges-ranges-placeholder/end"><span class="kw2887">ranges::<span class="me2">end</span></span></a><span class="br0">(</span>base_<span class="br0">)</span><span class="sy4">;</span> <span class="br0">}</span>
 
  <span class="kw1">private</span><span class="sy4">:</span>
    V base_ <span class="sy1">=</span> V<span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>                                      <span class="co1">// exposition only</span>
    <span class="coMULTI">/*copyable-box*/</span><span class="sy1">&lt;</span>Pred<span class="sy1">&gt;</span> pred_<span class="sy4">;</span>                       <span class="co1">// exposition only</span>
  <span class="br0">}</span><span class="sy4">;</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> R, <span class="kw1">class</span> Pred<span class="sy1">&gt;</span>
    drop_while_view<span class="br0">(</span>R<span class="sy3">&amp;&amp;</span>, Pred<span class="br0">)</span> <span class="sy2">-</span><span class="sy1">&gt;</span> drop_while_view<span class="sy1">&lt;</span><a href="../ranges/all_view.html"><span class="kw2919">views::<span class="me2">all_t</span></span></a><span class="sy1">&lt;</span>R<span class="sy1">&gt;</span>, Pred<span class="sy1">&gt;</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<h4><span class="mw-headline" id="Class_template_std::ranges::join_view">Class template <span class="t-lc">std::ranges::join_view</span></span></h4>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">namespace</span> std<span class="sy4">::</span><span class="me2">ranges</span> <span class="br0">{</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span>input_range V<span class="sy1">&gt;</span>
    requires view<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> input_range<span class="sy1">&lt;</span>range_reference_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;&gt;</span>
  <span class="kw1">class</span> join_view <span class="sy4">:</span> <span class="kw1">public</span> view_interface<span class="sy1">&lt;</span>join_view<span class="sy1">&lt;</span>V<span class="sy1">&gt;&gt;</span> <span class="br0">{</span>
  <span class="kw1">private</span><span class="sy4">:</span>
    <span class="kw1">using</span> InnerRng <span class="sy1">=</span> range_reference_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span><span class="sy4">;</span>                  <span class="co1">// exposition only</span>
 
    <span class="co1">// class template join_view::iterator</span>
    <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw4">bool</span> Const<span class="sy1">&gt;</span>
      <span class="kw1">struct</span> iterator<span class="sy4">;</span>                                      <span class="co1">// exposition only</span>
 
    <span class="co1">// class template join_view::sentinel</span>
    <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw4">bool</span> Const<span class="sy1">&gt;</span>
      <span class="kw1">struct</span> sentinel<span class="sy4">;</span>                                      <span class="co1">// exposition only</span>
 
    V base_ <span class="sy1">=</span> V<span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>                                          <span class="co1">// exposition only</span>
 
    <span class="coMULTI">/*non-propagating-cache*/</span><span class="sy1">&lt;</span>remove_cv_t<span class="sy1">&lt;</span>InnerRng<span class="sy1">&gt;&gt;</span>inner_<span class="sy4">;</span>
      <span class="co1">// exposition only, present only when !is_reference_v&lt;InnerRng&gt;</span>
 
  <span class="kw1">public</span><span class="sy4">:</span>
    join_view<span class="br0">(</span><span class="br0">)</span> requires default_initializable<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> <span class="sy1">=</span> <span class="kw1">default</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> <span class="kw1">explicit</span> join_view<span class="br0">(</span>V base<span class="br0">)</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> V base<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span><span class="sy3">&amp;</span> requires copy_constructible<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> <span class="br0">{</span> <span class="kw1">return</span> base_<span class="sy4">;</span> <span class="br0">}</span>
    <span class="kw4">constexpr</span> V base<span class="br0">(</span><span class="br0">)</span> <span class="sy3">&amp;&amp;</span> <span class="br0">{</span> <span class="kw1">return</span> std<span class="sy4">::</span><span class="me2">move</span><span class="br0">(</span>base_<span class="br0">)</span><span class="sy4">;</span> <span class="br0">}</span>
 
    <span class="kw4">constexpr</span> <span class="kw4">auto</span> begin<span class="br0">(</span><span class="br0">)</span> <span class="br0">{</span>
      <span class="kw4">constexpr</span> <span class="kw4">bool</span> use_const <span class="sy1">=</span> <span class="coMULTI">/*simple-view*/</span><span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
                                 is_reference_v<span class="sy1">&lt;</span>range_reference_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;&gt;</span><span class="sy4">;</span>
      <span class="kw1">return</span> iterator<span class="sy1">&lt;</span>use_const<span class="sy1">&gt;</span><span class="br0">{</span><span class="sy2">*</span>this, <a href="../../../http:/en.cppreference.com/w/cpp/ranges-ranges-placeholder/begin"><span class="kw2885">ranges::<span class="me2">begin</span></span></a><span class="br0">(</span>base_<span class="br0">)</span><span class="br0">}</span><span class="sy4">;</span>
    <span class="br0">}</span>
 
    <span class="kw4">constexpr</span> <span class="kw4">auto</span> begin<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span>
      requires input_range<span class="sy1">&lt;</span><span class="kw4">const</span> V<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
               is_reference_v<span class="sy1">&lt;</span>range_reference_t<span class="sy1">&lt;</span><span class="kw4">const</span> V<span class="sy1">&gt;&gt;</span>
    <span class="br0">{</span> <span class="kw1">return</span> iterator<span class="sy1">&lt;</span><span class="kw2">true</span><span class="sy1">&gt;</span><span class="br0">{</span><span class="sy2">*</span>this, <a href="../../../http:/en.cppreference.com/w/cpp/ranges-ranges-placeholder/begin"><span class="kw2885">ranges::<span class="me2">begin</span></span></a><span class="br0">(</span>base_<span class="br0">)</span><span class="br0">}</span><span class="sy4">;</span> <span class="br0">}</span>
 
    <span class="kw4">constexpr</span> <span class="kw4">auto</span> end<span class="br0">(</span><span class="br0">)</span> <span class="br0">{</span>
      <span class="kw1">if</span> <span class="kw4">constexpr</span> <span class="br0">(</span>forward_range<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
                    is_reference_v<span class="sy1">&lt;</span>InnerRng<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> forward_range<span class="sy1">&lt;</span>InnerRng<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
                    common_range<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> common_range<span class="sy1">&lt;</span>InnerRng<span class="sy1">&gt;</span><span class="br0">)</span>
        <span class="kw1">return</span> iterator<span class="sy1">&lt;</span><span class="coMULTI">/*simple-view*/</span><span class="sy1">&lt;</span>V<span class="sy1">&gt;&gt;</span><span class="br0">{</span><span class="sy2">*</span>this, <a href="../../../http:/en.cppreference.com/w/cpp/ranges-ranges-placeholder/end"><span class="kw2887">ranges::<span class="me2">end</span></span></a><span class="br0">(</span>base_<span class="br0">)</span><span class="br0">}</span><span class="sy4">;</span>
      <span class="kw1">else</span>
        <span class="kw1">return</span> sentinel<span class="sy1">&lt;</span><span class="coMULTI">/*simple-view*/</span><span class="sy1">&lt;</span>V<span class="sy1">&gt;&gt;</span><span class="br0">{</span><span class="sy2">*</span>this<span class="br0">}</span><span class="sy4">;</span>
    <span class="br0">}</span>
 
    <span class="kw4">constexpr</span> <span class="kw4">auto</span> end<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span>
      requires input_range<span class="sy1">&lt;</span><span class="kw4">const</span> V<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
               is_reference_v<span class="sy1">&lt;</span>range_reference_t<span class="sy1">&lt;</span><span class="kw4">const</span> V<span class="sy1">&gt;&gt;</span> <span class="br0">{</span>
      <span class="kw1">if</span> <span class="kw4">constexpr</span> <span class="br0">(</span>forward_range<span class="sy1">&lt;</span><span class="kw4">const</span> V<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
                    forward_range<span class="sy1">&lt;</span>range_reference_t<span class="sy1">&lt;</span><span class="kw4">const</span> V<span class="sy1">&gt;&gt;</span> <span class="sy3">&amp;&amp;</span>
                    common_range<span class="sy1">&lt;</span><span class="kw4">const</span> V<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
                    common_range<span class="sy1">&lt;</span>range_reference_t<span class="sy1">&lt;</span><span class="kw4">const</span> V<span class="sy1">&gt;&gt;</span><span class="br0">)</span>
        <span class="kw1">return</span> iterator<span class="sy1">&lt;</span><span class="kw2">true</span><span class="sy1">&gt;</span><span class="br0">{</span><span class="sy2">*</span>this, <a href="../../../http:/en.cppreference.com/w/cpp/ranges-ranges-placeholder/end"><span class="kw2887">ranges::<span class="me2">end</span></span></a><span class="br0">(</span>base_<span class="br0">)</span><span class="br0">}</span><span class="sy4">;</span>
      <span class="kw1">else</span>
        <span class="kw1">return</span> sentinel<span class="sy1">&lt;</span><span class="kw2">true</span><span class="sy1">&gt;</span><span class="br0">{</span><span class="sy2">*</span>this<span class="br0">}</span><span class="sy4">;</span>
    <span class="br0">}</span>
  <span class="br0">}</span><span class="sy4">;</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> R<span class="sy1">&gt;</span>
    <span class="kw1">explicit</span> join_view<span class="br0">(</span>R<span class="sy3">&amp;&amp;</span><span class="br0">)</span> <span class="sy2">-</span><span class="sy1">&gt;</span> join_view<span class="sy1">&lt;</span><a href="../ranges/all_view.html"><span class="kw2919">views::<span class="me2">all_t</span></span></a><span class="sy1">&lt;</span>R<span class="sy1">&gt;&gt;</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<h4><span class="mw-headline" id="Class_template_std::ranges::join_view::iterator">Class template <span class="t-lc">std::ranges::join_view::iterator</span></span></h4>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">namespace</span> std<span class="sy4">::</span><span class="me2">ranges</span> <span class="br0">{</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span>input_range V<span class="sy1">&gt;</span>
    requires view<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> input_range<span class="sy1">&lt;</span>range_reference_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;&gt;</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw4">bool</span> Const<span class="sy1">&gt;</span>
  <span class="kw1">struct</span> join_view<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">iterator</span> <span class="br0">{</span>
  <span class="kw1">private</span><span class="sy4">:</span>
    <span class="kw1">using</span> Parent    <span class="sy1">=</span> <span class="coMULTI">/*maybe-const*/</span><span class="sy1">&lt;</span>Const, join_view<span class="sy1">&gt;</span><span class="sy4">;</span>        <span class="co1">// exposition only</span>
    <span class="kw1">using</span> Base      <span class="sy1">=</span> <span class="coMULTI">/*maybe-const*/</span><span class="sy1">&lt;</span>Const, V<span class="sy1">&gt;</span><span class="sy4">;</span>                <span class="co1">// exposition only</span>
    <span class="kw1">using</span> OuterIter <span class="sy1">=</span> iterator_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span><span class="sy4">;</span>                         <span class="co1">// exposition only</span>
    <span class="kw1">using</span> InnerIter <span class="sy1">=</span> iterator_t<span class="sy1">&lt;</span>range_reference_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;&gt;</span><span class="sy4">;</span>      <span class="co1">// exposition only</span>
 
    <span class="kw4">static</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> <span class="coMULTI">/*ref-is-glvalue*/</span> <span class="sy1">=</span>                  <span class="co1">// exposition only</span>
      is_reference_v<span class="sy1">&lt;</span>range_reference_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;&gt;</span><span class="sy4">;</span>
 
    OuterIter outer_ <span class="sy1">=</span> OuterIter<span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>                             <span class="co1">// exposition only</span>
    InnerIter inner_ <span class="sy1">=</span> InnerIter<span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>                             <span class="co1">// exposition only</span>
    Parent<span class="sy2">*</span> parent_  <span class="sy1">=</span> nullptr<span class="sy4">;</span>                                 <span class="co1">// exposition only</span>
 
    <span class="kw4">constexpr</span> <span class="kw4">void</span> satisfy<span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>                                   <span class="co1">// exposition only</span>
 
  <span class="kw1">public</span><span class="sy4">:</span>
    <span class="kw1">using</span> iterator_concept  <span class="sy1">=</span> <span class="coMULTI">/* see description */</span><span class="sy4">;</span>
    <span class="kw1">using</span> iterator_category <span class="sy1">=</span> <span class="coMULTI">/* see description */</span><span class="sy4">;</span>            <span class="co1">// not always present</span>
    <span class="kw1">using</span> value_type        <span class="sy1">=</span> range_value_t<span class="sy1">&lt;</span>range_reference_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;&gt;</span><span class="sy4">;</span>
    <span class="kw1">using</span> difference_type   <span class="sy1">=</span> <span class="coMULTI">/* see description */</span><span class="sy4">;</span>
 
    iterator<span class="br0">(</span><span class="br0">)</span> requires default_initializable<span class="sy1">&lt;</span>OuterIter<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
                         default_initializable<span class="sy1">&lt;</span>InnerIter<span class="sy1">&gt;</span> <span class="sy1">=</span> <span class="kw1">default</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> iterator<span class="br0">(</span>Parent<span class="sy3">&amp;</span> parent, OuterIter outer<span class="br0">)</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> iterator<span class="br0">(</span>iterator<span class="sy1">&lt;</span><span class="sy3">!</span>Const<span class="sy1">&gt;</span> i<span class="br0">)</span>
      requires Const <span class="sy3">&amp;&amp;</span>
               convertible_to<span class="sy1">&lt;</span>iterator_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span>, OuterIter<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
               convertible_to<span class="sy1">&lt;</span>iterator_t<span class="sy1">&lt;</span>InnerRng<span class="sy1">&gt;</span>, InnerIter<span class="sy1">&gt;</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> decltype<span class="br0">(</span><span class="kw4">auto</span><span class="br0">)</span> operator<span class="sy2">*</span><span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span> <span class="br0">{</span> <span class="kw1">return</span> <span class="sy2">*</span>inner_<span class="sy4">;</span> <span class="br0">}</span>
 
    <span class="kw4">constexpr</span> InnerIter operator<span class="sy2">-</span><span class="sy1">&gt;</span><span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span>
      requires <span class="coMULTI">/*has-arrow*/</span><span class="sy1">&lt;</span>InnerIter<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> copyable<span class="sy1">&lt;</span>InnerIter<span class="sy1">&gt;</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> iterator<span class="sy3">&amp;</span> operator<span class="sy2">++</span><span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> <span class="kw4">void</span> operator<span class="sy2">++</span><span class="br0">(</span><span class="kw4">int</span><span class="br0">)</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> iterator operator<span class="sy2">++</span><span class="br0">(</span><span class="kw4">int</span><span class="br0">)</span>
      requires <span class="coMULTI">/*ref-is-glvalue*/</span> <span class="sy3">&amp;&amp;</span> forward_range<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
               forward_range<span class="sy1">&lt;</span>range_reference_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;&gt;</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> iterator<span class="sy3">&amp;</span> operator<span class="sy2">--</span><span class="br0">(</span><span class="br0">)</span>
      requires <span class="coMULTI">/*ref-is-glvalue*/</span> <span class="sy3">&amp;&amp;</span> bidirectional_range<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
               bidirectional_range<span class="sy1">&lt;</span>range_reference_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;&gt;</span> <span class="sy3">&amp;&amp;</span>
               common_range<span class="sy1">&lt;</span>range_reference_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;&gt;</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> iterator operator<span class="sy2">--</span><span class="br0">(</span><span class="kw4">int</span><span class="br0">)</span>
      requires <span class="coMULTI">/*ref-is-glvalue*/</span> <span class="sy3">&amp;&amp;</span> bidirectional_range<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
               bidirectional_range<span class="sy1">&lt;</span>range_reference_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;&gt;</span> <span class="sy3">&amp;&amp;</span>
               common_range<span class="sy1">&lt;</span>range_reference_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;&gt;</span><span class="sy4">;</span>
 
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> operator<span class="sy1">==</span><span class="br0">(</span><span class="kw4">const</span> iterator<span class="sy3">&amp;</span> x, <span class="kw4">const</span> iterator<span class="sy3">&amp;</span> y<span class="br0">)</span>
      requires <span class="coMULTI">/*ref-is-glvalue*/</span> <span class="sy3">&amp;&amp;</span> equality_comparable<span class="sy1">&lt;</span>iterator_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;&gt;</span> <span class="sy3">&amp;&amp;</span>
               equality_comparable<span class="sy1">&lt;</span>iterator_t<span class="sy1">&lt;</span>range_reference_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;&gt;&gt;</span><span class="sy4">;</span>
 
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> decltype<span class="br0">(</span><span class="kw4">auto</span><span class="br0">)</span> iter_move<span class="br0">(</span><span class="kw4">const</span> iterator<span class="sy3">&amp;</span> i<span class="br0">)</span>
    <span class="kw1">noexcept</span><span class="br0">(</span><span class="kw1">noexcept</span><span class="br0">(</span><a href="../iterator/ranges/iter_move.html"><span class="kw3143">ranges::<span class="me2">iter_move</span></span></a><span class="br0">(</span>i.<span class="me1">inner_</span><span class="br0">)</span><span class="br0">)</span><span class="br0">)</span> <span class="br0">{</span>
      <span class="kw1">return</span> <a href="../iterator/ranges/iter_move.html"><span class="kw3143">ranges::<span class="me2">iter_move</span></span></a><span class="br0">(</span>i.<span class="me1">inner_</span><span class="br0">)</span><span class="sy4">;</span>
    <span class="br0">}</span>
 
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> <span class="kw4">void</span> iter_swap<span class="br0">(</span><span class="kw4">const</span> iterator<span class="sy3">&amp;</span> x, <span class="kw4">const</span> iterator<span class="sy3">&amp;</span> y<span class="br0">)</span>
      <span class="kw1">noexcept</span><span class="br0">(</span><span class="kw1">noexcept</span><span class="br0">(</span><a href="../iterator/ranges/iter_swap.html"><span class="kw3278">ranges::<span class="me2">iter_swap</span></span></a><span class="br0">(</span>x.<span class="me1">inner_</span>, y.<span class="me1">inner_</span><span class="br0">)</span><span class="br0">)</span><span class="br0">)</span>
      requires indirectly_swappable<span class="sy1">&lt;</span>InnerIter<span class="sy1">&gt;</span><span class="sy4">;</span>
  <span class="br0">}</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<h4><span class="mw-headline" id="Class_template_std::ranges::join_view::sentinel">Class template <span class="t-lc">std::ranges::join_view::sentinel</span></span></h4>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">namespace</span> std<span class="sy4">::</span><span class="me2">ranges</span> <span class="br0">{</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span>input_range V<span class="sy1">&gt;</span>
    requires view<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> input_range<span class="sy1">&lt;</span>range_reference_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;&gt;</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw4">bool</span> Const<span class="sy1">&gt;</span>
  <span class="kw1">struct</span> join_view<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">sentinel</span> <span class="br0">{</span>
  <span class="kw1">private</span><span class="sy4">:</span>
    <span class="kw1">using</span> Parent <span class="sy1">=</span> <span class="coMULTI">/*maybe-const*/</span><span class="sy1">&lt;</span>Const, join_view<span class="sy1">&gt;</span><span class="sy4">;</span>       <span class="co1">// exposition only</span>
    <span class="kw1">using</span> Base <span class="sy1">=</span> <span class="coMULTI">/*maybe-const*/</span><span class="sy1">&lt;</span>Const, V<span class="sy1">&gt;</span><span class="sy4">;</span>                 <span class="co1">// exposition only</span>
    sentinel_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span> end_ <span class="sy1">=</span> sentinel_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span><span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>             <span class="co1">// exposition only</span>
 
  <span class="kw1">public</span><span class="sy4">:</span>
    sentinel<span class="br0">(</span><span class="br0">)</span> <span class="sy1">=</span> <span class="kw1">default</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> <span class="kw1">explicit</span> sentinel<span class="br0">(</span>Parent<span class="sy3">&amp;</span> parent<span class="br0">)</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> sentinel<span class="br0">(</span>sentinel<span class="sy1">&lt;</span><span class="sy3">!</span>Const<span class="sy1">&gt;</span> s<span class="br0">)</span>
      requires Const <span class="sy3">&amp;&amp;</span> convertible_to<span class="sy1">&lt;</span>sentinel_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span>, sentinel_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;&gt;</span><span class="sy4">;</span>
 
    <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw4">bool</span> OtherConst<span class="sy1">&gt;</span>
      requires sentinel_for<span class="sy1">&lt;</span>sentinel_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span>, iterator_t<span class="sy1">&lt;</span><span class="coMULTI">/*maybe-const*/</span><span class="sy1">&lt;</span>OtherConst, V<span class="sy1">&gt;&gt;&gt;</span>
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> operator<span class="sy1">==</span><span class="br0">(</span><span class="kw4">const</span> iterator<span class="sy1">&lt;</span>OtherConst<span class="sy1">&gt;</span><span class="sy3">&amp;</span> x, <span class="kw4">const</span> sentinel<span class="sy3">&amp;</span> y<span class="br0">)</span><span class="sy4">;</span>
  <span class="br0">}</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<h4><span class="mw-headline" id="Class_template_std::ranges::join_with_view">Class template <span class="t-lc">std::ranges::join_with_view</span></span></h4>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">namespace</span> std<span class="sy4">::</span><span class="me2">ranges</span> <span class="br0">{</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> R, <span class="kw1">class</span> P<span class="sy1">&gt;</span>
  concept <span class="coMULTI">/*compatible-joinable-ranges*/</span> <span class="sy1">=</span>            <span class="co1">// exposition only</span>
      common_with<span class="sy1">&lt;</span>range_value_t<span class="sy1">&lt;</span>R<span class="sy1">&gt;</span>, range_value_t<span class="sy1">&lt;</span>P<span class="sy1">&gt;&gt;</span> <span class="sy3">&amp;&amp;</span>
      common_reference_with<span class="sy1">&lt;</span>range_reference_t<span class="sy1">&lt;</span>R<span class="sy1">&gt;</span>, range_reference_t<span class="sy1">&lt;</span>P<span class="sy1">&gt;&gt;</span> <span class="sy3">&amp;&amp;</span>
      common_reference_with<span class="sy1">&lt;</span>range_rvalue_reference_t<span class="sy1">&lt;</span>R<span class="sy1">&gt;</span>, range_rvalue_reference_t<span class="sy1">&lt;</span>P<span class="sy1">&gt;&gt;</span><span class="sy4">;</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> R<span class="sy1">&gt;</span>
  concept <span class="coMULTI">/*bidirectional-common*/</span> <span class="sy1">=</span>                  <span class="co1">// exposition only</span>
        bidirectional_range<span class="sy1">&lt;</span>R<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> common_range<span class="sy1">&lt;</span>R<span class="sy1">&gt;</span><span class="sy4">;</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span>input_range V, forward_range Pattern<span class="sy1">&gt;</span>
    requires view<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> input_range<span class="sy1">&lt;</span>range_reference_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;&gt;</span>
          <span class="sy3">&amp;&amp;</span> view<span class="sy1">&lt;</span>Pattern<span class="sy1">&gt;</span>
          <span class="sy3">&amp;&amp;</span> <span class="coMULTI">/*compatible-joinable-ranges*/</span><span class="sy1">&lt;</span>range_reference_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span>, Pattern<span class="sy1">&gt;</span>
  <span class="kw1">class</span> join_with_view <span class="sy4">:</span> <span class="kw1">public</span> view_interface<span class="sy1">&lt;</span>join_with_view<span class="sy1">&lt;</span>V, Pattern<span class="sy1">&gt;&gt;</span> <span class="br0">{</span>
    <span class="kw1">using</span> InnerRng <span class="sy1">=</span> range_reference_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span><span class="sy4">;</span>             <span class="co1">// exposition only</span>
 
    V base_ <span class="sy1">=</span> V<span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>                                          <span class="co1">// exposition only</span>
        <span class="co1">// exposition only, present only when !is_reference_v&lt;inner-rng&gt;</span>
    <span class="coMULTI">/*non-propagating-cache*/</span><span class="sy1">&lt;</span>remove_cv_t<span class="sy1">&lt;</span>InnerRng<span class="sy1">&gt;&gt;</span> inner_<span class="sy4">;</span>
    Pattern pattern_ <span class="sy1">=</span> Pattern<span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>                           <span class="co1">// exposition only</span>
 
    <span class="co1">// class template join_with_view::iterator</span>
    <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw4">bool</span> Const<span class="sy1">&gt;</span> <span class="kw1">struct</span> iterator<span class="sy4">;</span>                   <span class="co1">// exposition only</span>
 
    <span class="co1">// class template join_with_view::sentinel</span>
    <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw4">bool</span> Const<span class="sy1">&gt;</span> <span class="kw1">struct</span> sentinel<span class="sy4">;</span>                   <span class="co1">// exposition only</span>
 
  <span class="kw1">public</span><span class="sy4">:</span>
    join_with_view<span class="br0">(</span><span class="br0">)</span>
      requires default_initializable<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> default_initializable<span class="sy1">&lt;</span>Pattern<span class="sy1">&gt;</span> <span class="sy1">=</span> <span class="kw1">default</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> join_with_view<span class="br0">(</span>V base, Pattern pattern<span class="br0">)</span><span class="sy4">;</span>
 
    <span class="kw1">template</span><span class="sy1">&lt;</span>input_range R<span class="sy1">&gt;</span>
      requires constructible_from<span class="sy1">&lt;</span>V, <a href="../ranges/all_view.html"><span class="kw2919">views::<span class="me2">all_t</span></span></a><span class="sy1">&lt;</span>R<span class="sy1">&gt;&gt;</span> <span class="sy3">&amp;&amp;</span>
               constructible_from<span class="sy1">&lt;</span>Pattern, single_view<span class="sy1">&lt;</span>range_value_t<span class="sy1">&lt;</span>InnerRng<span class="sy1">&gt;&gt;&gt;</span>
    <span class="kw4">constexpr</span> join_with_view<span class="br0">(</span>R<span class="sy3">&amp;&amp;</span> r, range_value_t<span class="sy1">&lt;</span>InnerRng<span class="sy1">&gt;</span> e<span class="br0">)</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> V base<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span> <span class="sy3">&amp;</span> requires copy_constructible<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> <span class="br0">{</span> <span class="kw1">return</span> base_<span class="sy4">;</span> <span class="br0">}</span>
    <span class="kw4">constexpr</span> V base<span class="br0">(</span><span class="br0">)</span> <span class="sy3">&amp;&amp;</span> <span class="br0">{</span> <span class="kw1">return</span> std<span class="sy4">::</span><span class="me2">move</span><span class="br0">(</span>base_<span class="br0">)</span><span class="sy4">;</span> <span class="br0">}</span>
 
    <span class="kw4">constexpr</span> <span class="kw4">auto</span> begin<span class="br0">(</span><span class="br0">)</span> <span class="br0">{</span>
      <span class="kw4">constexpr</span> <span class="kw4">bool</span> use_const <span class="sy1">=</span>
          <span class="coMULTI">/*simple-view*/</span><span class="sy1">&lt;</span>V<span class="sy1">&gt;</span>
       <span class="sy3">&amp;&amp;</span> is_reference_v<span class="sy1">&lt;</span>InnerRng<span class="sy1">&gt;</span>
       <span class="sy3">&amp;&amp;</span> <span class="coMULTI">/*simple-view*/</span><span class="sy1">&lt;</span>Pattern<span class="sy1">&gt;</span><span class="sy4">;</span>
      <span class="kw1">return</span> iterator<span class="sy1">&lt;</span>use_const<span class="sy1">&gt;</span><span class="br0">{</span><span class="sy2">*</span>this, <a href="../../../http:/en.cppreference.com/w/cpp/ranges-ranges-placeholder/begin"><span class="kw2885">ranges::<span class="me2">begin</span></span></a><span class="br0">(</span>base_<span class="br0">)</span><span class="br0">}</span><span class="sy4">;</span>
    <span class="br0">}</span>
    <span class="kw4">constexpr</span> <span class="kw4">auto</span> begin<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span>
      requires input_range<span class="sy1">&lt;</span><span class="kw4">const</span> V<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
               forward_range<span class="sy1">&lt;</span><span class="kw4">const</span> Pattern<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
               is_reference_v<span class="sy1">&lt;</span>range_reference_t<span class="sy1">&lt;</span><span class="kw4">const</span> V<span class="sy1">&gt;&gt;</span> <span class="br0">{</span>
      <span class="kw1">return</span> iterator<span class="sy1">&lt;</span><span class="kw2">true</span><span class="sy1">&gt;</span><span class="br0">{</span><span class="sy2">*</span>this, <a href="../../../http:/en.cppreference.com/w/cpp/ranges-ranges-placeholder/begin"><span class="kw2885">ranges::<span class="me2">begin</span></span></a><span class="br0">(</span>base_<span class="br0">)</span><span class="br0">}</span><span class="sy4">;</span>
    <span class="br0">}</span>
 
    <span class="kw4">constexpr</span> <span class="kw4">auto</span> end<span class="br0">(</span><span class="br0">)</span> <span class="br0">{</span>
      <span class="kw1">if</span> <span class="kw4">constexpr</span> <span class="br0">(</span>forward_range<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
                    is_reference_v<span class="sy1">&lt;</span>InnerRng<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> forward_range<span class="sy1">&lt;</span>InnerRng<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
                    common_range<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> common_range<span class="sy1">&lt;</span>InnerRng<span class="sy1">&gt;</span><span class="br0">)</span>
        <span class="kw1">return</span> iterator<span class="sy1">&lt;</span><span class="coMULTI">/*simple-view*/</span><span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> <span class="coMULTI">/*simple-view*/</span><span class="sy1">&lt;</span>Pattern<span class="sy1">&gt;&gt;</span><span class="br0">{</span>
          <span class="sy2">*</span>this, <a href="../../../http:/en.cppreference.com/w/cpp/ranges-ranges-placeholder/end"><span class="kw2887">ranges::<span class="me2">end</span></span></a><span class="br0">(</span>base_<span class="br0">)</span>
        <span class="br0">}</span><span class="sy4">;</span>
      <span class="kw1">else</span>
        <span class="kw1">return</span> sentinel<span class="sy1">&lt;</span><span class="coMULTI">/*simple-view*/</span><span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> <span class="coMULTI">/*simple-view*/</span><span class="sy1">&lt;</span>Pattern<span class="sy1">&gt;&gt;</span><span class="br0">{</span><span class="sy2">*</span>this<span class="br0">}</span><span class="sy4">;</span>
    <span class="br0">}</span>
    <span class="kw4">constexpr</span> <span class="kw4">auto</span> end<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span>
      requires input_range<span class="sy1">&lt;</span><span class="kw4">const</span> V<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> forward_range<span class="sy1">&lt;</span><span class="kw4">const</span> Pattern<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
               is_reference_v<span class="sy1">&lt;</span>range_reference_t<span class="sy1">&lt;</span><span class="kw4">const</span> V<span class="sy1">&gt;&gt;</span> <span class="br0">{</span>
      <span class="kw1">using</span> InnerConstRng <span class="sy1">=</span> range_reference_t<span class="sy1">&lt;</span><span class="kw4">const</span> V<span class="sy1">&gt;</span><span class="sy4">;</span>
      <span class="kw1">if</span> <span class="kw4">constexpr</span> <span class="br0">(</span>forward_range<span class="sy1">&lt;</span><span class="kw4">const</span> V<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> forward_range<span class="sy1">&lt;</span>InnerConstRng<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
                    common_range<span class="sy1">&lt;</span><span class="kw4">const</span> V<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> common_range<span class="sy1">&lt;</span>InnerConstRng<span class="sy1">&gt;</span><span class="br0">)</span>
        <span class="kw1">return</span> iterator<span class="sy1">&lt;</span><span class="kw2">true</span><span class="sy1">&gt;</span><span class="br0">{</span><span class="sy2">*</span>this, <a href="../../../http:/en.cppreference.com/w/cpp/ranges-ranges-placeholder/end"><span class="kw2887">ranges::<span class="me2">end</span></span></a><span class="br0">(</span>base_<span class="br0">)</span><span class="br0">}</span><span class="sy4">;</span>
      <span class="kw1">else</span>
        <span class="kw1">return</span> sentinel<span class="sy1">&lt;</span><span class="kw2">true</span><span class="sy1">&gt;</span><span class="br0">{</span><span class="sy2">*</span>this<span class="br0">}</span><span class="sy4">;</span>
    <span class="br0">}</span>
  <span class="br0">}</span><span class="sy4">;</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> R, <span class="kw1">class</span> P<span class="sy1">&gt;</span>
    join_with_view<span class="br0">(</span>R<span class="sy3">&amp;&amp;</span>, P<span class="sy3">&amp;&amp;</span><span class="br0">)</span> <span class="sy2">-</span><span class="sy1">&gt;</span> join_with_view<span class="sy1">&lt;</span><a href="../ranges/all_view.html"><span class="kw2919">views::<span class="me2">all_t</span></span></a><span class="sy1">&lt;</span>R<span class="sy1">&gt;</span>, <a href="../ranges/all_view.html"><span class="kw2919">views::<span class="me2">all_t</span></span></a><span class="sy1">&lt;</span>P<span class="sy1">&gt;&gt;</span><span class="sy4">;</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span>input_range R<span class="sy1">&gt;</span>
    join_with_view<span class="br0">(</span>R<span class="sy3">&amp;&amp;</span>, range_value_t<span class="sy1">&lt;</span>range_reference_t<span class="sy1">&lt;</span>R<span class="sy1">&gt;&gt;</span><span class="br0">)</span>
      <span class="sy2">-</span><span class="sy1">&gt;</span> join_with_view<span class="sy1">&lt;</span><a href="../ranges/all_view.html"><span class="kw2919">views::<span class="me2">all_t</span></span></a><span class="sy1">&lt;</span>R<span class="sy1">&gt;</span>, single_view<span class="sy1">&lt;</span>range_value_t<span class="sy1">&lt;</span>range_reference_t<span class="sy1">&lt;</span>R<span class="sy1">&gt;&gt;&gt;&gt;</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<h4><span class="mw-headline" id="Class_template_std::ranges::join_with_view::iterator">Class template <span class="t-lc">std::ranges::join_with_view::iterator</span></span></h4>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">namespace</span> std<span class="sy4">::</span><span class="me2">ranges</span> <span class="br0">{</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span>input_range V, forward_range Pattern<span class="sy1">&gt;</span>
    requires view<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> input_range<span class="sy1">&lt;</span>range_reference_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;&gt;</span>
          <span class="sy3">&amp;&amp;</span> view<span class="sy1">&lt;</span>Pattern<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> <span class="coMULTI">/*compatible-joinable-ranges*/</span><span class="sy1">&lt;</span>range_reference_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span>, Pattern<span class="sy1">&gt;</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw4">bool</span> Const<span class="sy1">&gt;</span>
  <span class="kw1">class</span> join_with_view<span class="sy1">&lt;</span>V, Pattern<span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">iterator</span> <span class="br0">{</span>
    <span class="kw1">using</span> Parent <span class="sy1">=</span> <span class="coMULTI">/*maybe-const*/</span><span class="sy1">&lt;</span>Const, join_with_view<span class="sy1">&gt;</span><span class="sy4">;</span>              <span class="co1">// exposition only</span>
    <span class="kw1">using</span> Base <span class="sy1">=</span> <span class="coMULTI">/*maybe-const*/</span><span class="sy1">&lt;</span>Const, V<span class="sy1">&gt;</span><span class="sy4">;</span>                             <span class="co1">// exposition only</span>
    <span class="kw1">using</span> InnerBase <span class="sy1">=</span> range_reference_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span><span class="sy4">;</span>                          <span class="co1">// exposition only</span>
    <span class="kw1">using</span> PatternBase <span class="sy1">=</span> <span class="coMULTI">/*maybe-const*/</span><span class="sy1">&lt;</span>Const, Pattern<span class="sy1">&gt;</span><span class="sy4">;</span>                <span class="co1">// exposition only</span>
 
    <span class="kw1">using</span> OuterIter <span class="sy1">=</span> iterator_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span><span class="sy4">;</span>                                 <span class="co1">// exposition only</span>
    <span class="kw1">using</span> InnerIter <span class="sy1">=</span> iterator_t<span class="sy1">&lt;</span>InnerBase<span class="sy1">&gt;</span><span class="sy4">;</span>                            <span class="co1">// exposition only</span>
    <span class="kw1">using</span> PatternIter <span class="sy1">=</span> iterator_t<span class="sy1">&lt;</span>PatternBase<span class="sy1">&gt;</span><span class="sy4">;</span>                        <span class="co1">// exposition only</span>
 
    <span class="kw4">static</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> <span class="coMULTI">/*ref-is-glvalue*/</span> <span class="sy1">=</span> is_reference_v<span class="sy1">&lt;</span>InnerBase<span class="sy1">&gt;</span><span class="sy4">;</span> <span class="co1">// exposition only</span>
 
    Parent<span class="sy2">*</span> parent_ <span class="sy1">=</span> nullptr<span class="sy4">;</span>                                          <span class="co1">// exposition only</span>
    OuterIter outer_it_ <span class="sy1">=</span> OuterIter<span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>                                  <span class="co1">// exposition only</span>
    variant<span class="sy1">&lt;</span>PatternIter, InnerIter<span class="sy1">&gt;</span> inner_it_<span class="sy4">;</span>                          <span class="co1">// exposition only</span>
 
    <span class="kw4">constexpr</span> iterator<span class="br0">(</span>Parent<span class="sy3">&amp;</span> parent, iterator_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span> outer<span class="br0">)</span><span class="sy4">;</span>         <span class="co1">// exposition only</span>
    <span class="kw4">constexpr</span> <span class="kw4">auto</span><span class="sy3">&amp;&amp;</span> <span class="coMULTI">/*update-inner*/</span><span class="br0">(</span><span class="kw4">const</span> OuterIter<span class="sy3">&amp;</span><span class="br0">)</span><span class="sy4">;</span>                <span class="co1">// exposition only</span>
    <span class="kw4">constexpr</span> <span class="kw4">auto</span><span class="sy3">&amp;&amp;</span> <span class="coMULTI">/*get-inner*/</span><span class="br0">(</span><span class="kw4">const</span> OuterIter<span class="sy3">&amp;</span><span class="br0">)</span><span class="sy4">;</span>                   <span class="co1">// exposition only</span>
    <span class="kw4">constexpr</span> <span class="kw4">void</span> <span class="coMULTI">/*satisfy*/</span><span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>                                       <span class="co1">// exposition only</span>
 
  <span class="kw1">public</span><span class="sy4">:</span>
    <span class="kw1">using</span> iterator_concept <span class="sy1">=</span> <span class="coMULTI">/* see description */</span><span class="sy4">;</span>
    <span class="kw1">using</span> iterator_category <span class="sy1">=</span> <span class="coMULTI">/* see description */</span><span class="sy4">;</span>                <span class="co1">// not always present</span>
    <span class="kw1">using</span> value_type <span class="sy1">=</span> <span class="coMULTI">/* see description */</span><span class="sy4">;</span>
    <span class="kw1">using</span> difference_type <span class="sy1">=</span> <span class="coMULTI">/* see description */</span><span class="sy4">;</span>
 
    iterator<span class="br0">(</span><span class="br0">)</span> requires default_initializable<span class="sy1">&lt;</span>OuterIter<span class="sy1">&gt;</span> <span class="sy1">=</span> <span class="kw1">default</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> iterator<span class="br0">(</span>iterator<span class="sy1">&lt;</span><span class="sy3">!</span>Const<span class="sy1">&gt;</span> i<span class="br0">)</span>
        requires Const <span class="sy3">&amp;&amp;</span> convertible_to<span class="sy1">&lt;</span>iterator_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span>, OuterIter<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
                 convertible_to<span class="sy1">&lt;</span>iterator_t<span class="sy1">&lt;</span>InnerRng<span class="sy1">&gt;</span>, InnerIter<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
                 convertible_to<span class="sy1">&lt;</span>iterator_t<span class="sy1">&lt;</span>Pattern<span class="sy1">&gt;</span>, PatternIter<span class="sy1">&gt;</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> decltype<span class="br0">(</span><span class="kw4">auto</span><span class="br0">)</span> operator<span class="sy2">*</span><span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> iterator<span class="sy3">&amp;</span> operator<span class="sy2">++</span><span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> <span class="kw4">void</span> operator<span class="sy2">++</span><span class="br0">(</span><span class="kw4">int</span><span class="br0">)</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> iterator operator<span class="sy2">++</span><span class="br0">(</span><span class="kw4">int</span><span class="br0">)</span>
        requires <span class="coMULTI">/*ref-is-glvalue*/</span> <span class="sy3">&amp;&amp;</span> forward_iterator<span class="sy1">&lt;</span>OuterIter<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
                 forward_iterator<span class="sy1">&lt;</span>InnerIter<span class="sy1">&gt;</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> iterator<span class="sy3">&amp;</span> operator<span class="sy2">--</span><span class="br0">(</span><span class="br0">)</span>
        requires <span class="coMULTI">/*ref-is-glvalue*/</span> <span class="sy3">&amp;&amp;</span> bidirectional_range<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
                 <span class="coMULTI">/*bidirectional-common*/</span><span class="sy1">&lt;</span>InnerBase<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
                 <span class="coMULTI">/*bidirectional-common*/</span><span class="sy1">&lt;</span>PatternBase<span class="sy1">&gt;</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> iterator operator<span class="sy2">--</span><span class="br0">(</span><span class="kw4">int</span><span class="br0">)</span>
        requires <span class="coMULTI">/*ref-is-glvalue*/</span> <span class="sy3">&amp;&amp;</span> bidirectional_range<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
                 <span class="coMULTI">/*bidirectional-common*/</span><span class="sy1">&lt;</span>InnerBase<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
                 <span class="coMULTI">/*bidirectional-common*/</span><span class="sy1">&lt;</span>PatternBase<span class="sy1">&gt;</span><span class="sy4">;</span>
 
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> operator<span class="sy1">==</span><span class="br0">(</span><span class="kw4">const</span> iterator<span class="sy3">&amp;</span> x, <span class="kw4">const</span> iterator<span class="sy3">&amp;</span> y<span class="br0">)</span>
        requires <span class="coMULTI">/*ref-is-glvalue*/</span> <span class="sy3">&amp;&amp;</span> equality_comparable<span class="sy1">&lt;</span>OuterIter<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
                 equality_comparable<span class="sy1">&lt;</span>InnerIter<span class="sy1">&gt;</span><span class="sy4">;</span>
 
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> decltype<span class="br0">(</span><span class="kw4">auto</span><span class="br0">)</span> iter_move<span class="br0">(</span><span class="kw4">const</span> iterator<span class="sy3">&amp;</span> x<span class="br0">)</span> <span class="br0">{</span>
      <span class="kw1">using</span> rvalue_reference <span class="sy1">=</span> common_reference_t<span class="sy1">&lt;</span>
        iter_rvalue_reference_t<span class="sy1">&lt;</span>InnerIter<span class="sy1">&gt;</span>,
        iter_rvalue_reference_t<span class="sy1">&lt;</span>PatternIter<span class="sy1">&gt;&gt;</span><span class="sy4">;</span>
      <span class="kw1">return</span> visit<span class="sy1">&lt;</span>rvalue_reference<span class="sy1">&gt;</span><span class="br0">(</span><a href="../iterator/ranges/iter_move.html"><span class="kw3143">ranges::<span class="me2">iter_move</span></span></a>, x.<span class="me1">inner_it_</span><span class="br0">)</span><span class="sy4">;</span>
    <span class="br0">}</span>
 
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> <span class="kw4">void</span> iter_swap<span class="br0">(</span><span class="kw4">const</span> iterator<span class="sy3">&amp;</span> x, <span class="kw4">const</span> iterator<span class="sy3">&amp;</span> y<span class="br0">)</span>
        requires indirectly_swappable<span class="sy1">&lt;</span>InnerIter, PatternIter<span class="sy1">&gt;</span> <span class="br0">{</span>
      visit<span class="br0">(</span><a href="../iterator/ranges/iter_swap.html"><span class="kw3278">ranges::<span class="me2">iter_swap</span></span></a>, x.<span class="me1">inner_it_</span>, y.<span class="me1">inner_it_</span><span class="br0">)</span><span class="sy4">;</span>
    <span class="br0">}</span>
  <span class="br0">}</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<h4><span class="mw-headline" id="Class_template_std::ranges::join_with_view::sentinel">Class template <span class="t-lc">std::ranges::join_with_view::sentinel</span></span></h4>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">namespace</span> std<span class="sy4">::</span><span class="me2">ranges</span> <span class="br0">{</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span>input_range V, forward_range Pattern<span class="sy1">&gt;</span>
    requires view<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> input_range<span class="sy1">&lt;</span>range_reference_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;&gt;</span>
          <span class="sy3">&amp;&amp;</span> view<span class="sy1">&lt;</span>Pattern<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> <span class="coMULTI">/*compatible-joinable-ranges*/</span><span class="sy1">&lt;</span>range_reference_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span>, Pattern<span class="sy1">&gt;</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw4">bool</span> Const<span class="sy1">&gt;</span>
  <span class="kw1">class</span> join_with_view<span class="sy1">&lt;</span>V, Pattern<span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">sentinel</span> <span class="br0">{</span>
    <span class="kw1">using</span> Parent <span class="sy1">=</span> <span class="coMULTI">/*maybe-const*/</span><span class="sy1">&lt;</span>Const, join_with_view<span class="sy1">&gt;</span><span class="sy4">;</span>  <span class="co1">// exposition only</span>
    <span class="kw1">using</span> Base <span class="sy1">=</span> <span class="coMULTI">/*maybe-const*/</span><span class="sy1">&lt;</span>Const, V<span class="sy1">&gt;</span><span class="sy4">;</span>                 <span class="co1">// exposition only</span>
    sentinel_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span> end_ <span class="sy1">=</span> sentinel_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span><span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>             <span class="co1">// exposition only</span>
 
    <span class="kw4">constexpr</span> <span class="kw1">explicit</span> sentinel<span class="br0">(</span>Parent<span class="sy3">&amp;</span> parent<span class="br0">)</span><span class="sy4">;</span>            <span class="co1">// exposition only</span>
 
  <span class="kw1">public</span><span class="sy4">:</span>
    sentinel<span class="br0">(</span><span class="br0">)</span> <span class="sy1">=</span> <span class="kw1">default</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> sentinel<span class="br0">(</span>sentinel<span class="sy1">&lt;</span><span class="sy3">!</span>Const<span class="sy1">&gt;</span> s<span class="br0">)</span>
      requires Const <span class="sy3">&amp;&amp;</span> convertible_to<span class="sy1">&lt;</span>sentinel_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span>, sentinel_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;&gt;</span><span class="sy4">;</span>
 
    <span class="kw1">template</span> <span class="sy1">&lt;</span><span class="kw4">bool</span> OtherConst<span class="sy1">&gt;</span>
      requires sentinel_for<span class="sy1">&lt;</span>sentinel_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span>, iterator_t<span class="sy1">&lt;</span><span class="coMULTI">/*maybe-const*/</span><span class="sy1">&lt;</span>OtherConst, V<span class="sy1">&gt;&gt;&gt;</span>
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> operator<span class="sy1">==</span><span class="br0">(</span><span class="kw4">const</span> iterator<span class="sy1">&lt;</span>OtherConst<span class="sy1">&gt;</span><span class="sy3">&amp;</span> x, <span class="kw4">const</span> sentinel<span class="sy3">&amp;</span> y<span class="br0">)</span><span class="sy4">;</span>
  <span class="br0">}</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<h4><span class="mw-headline" id="Class_template_std::ranges::lazy_split_view">Class template <span class="t-lc">std::ranges::lazy_split_view</span></span></h4>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">namespace</span> std<span class="sy4">::</span><span class="me2">ranges</span> <span class="br0">{</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw4">auto</span><span class="sy1">&gt;</span> <span class="kw1">struct</span> <span class="coMULTI">/*require-constant*/</span><span class="sy4">;</span>                       <span class="co1">// exposition only</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> R<span class="sy1">&gt;</span>
  concept <span class="coMULTI">/*tiny-range*/</span> <span class="sy1">=</span>                                          <span class="co1">// exposition only</span>
    sized_range<span class="sy1">&lt;</span>R<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
    requires <span class="br0">{</span> <span class="kw1">typename</span> <span class="coMULTI">/*require-constant*/</span><span class="sy1">&lt;</span>remove_reference_t<span class="sy1">&lt;</span>R<span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">size</span><span class="br0">(</span><span class="br0">)</span><span class="sy1">&gt;</span><span class="sy4">;</span> <span class="br0">}</span> <span class="sy3">&amp;&amp;</span>
    <span class="br0">(</span>remove_reference_t<span class="sy1">&lt;</span>R<span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">size</span><span class="br0">(</span><span class="br0">)</span> <span class="sy1">&lt;=</span> <span class="nu0">1</span><span class="br0">)</span><span class="sy4">;</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span>input_range V, forward_range Pattern<span class="sy1">&gt;</span>
    requires view<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> view<span class="sy1">&lt;</span>Pattern<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
             indirectly_comparable<span class="sy1">&lt;</span>iterator_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span>, iterator_t<span class="sy1">&lt;</span>Pattern<span class="sy1">&gt;</span>, <a href="../functional/ranges/equal_to.html"><span class="kw2844">ranges::<span class="me2">equal_to</span></span></a><span class="sy1">&gt;</span>
             <span class="sy3">&amp;&amp;</span> <span class="br0">(</span>forward_range<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> <span class="sy3">||</span> <span class="coMULTI">/*tiny-range*/</span><span class="sy1">&lt;</span>Pattern<span class="sy1">&gt;</span><span class="br0">)</span>
  <span class="kw1">class</span> lazy_split_view <span class="sy4">:</span> <span class="kw1">public</span> view_interface<span class="sy1">&lt;</span>lazy_split_view<span class="sy1">&lt;</span>V, Pattern<span class="sy1">&gt;&gt;</span> <span class="br0">{</span>
  <span class="kw1">private</span><span class="sy4">:</span>
    V base_ <span class="sy1">=</span> V<span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>                                      <span class="co1">// exposition only</span>
    Pattern pattern_ <span class="sy1">=</span> Pattern<span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>                       <span class="co1">// exposition only</span>
 
    <span class="coMULTI">/*non-propagating-cache*/</span><span class="sy1">&lt;</span>iterator_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;&gt;</span> current_<span class="sy4">;</span>  <span class="co1">// exposition only, present only</span>
                                                        <span class="co1">// if !forward_range&lt;V&gt;</span>
 
    <span class="co1">// class template lazy_split_view::/*outer-iterator*/</span>
    <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw4">bool</span><span class="sy1">&gt;</span> <span class="kw1">struct</span> <span class="coMULTI">/*outer-iterator*/</span><span class="sy4">;</span>           <span class="co1">// exposition only</span>
 
    <span class="co1">// class template lazy_split_view::/*inner-iterator*/</span>
    <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw4">bool</span><span class="sy1">&gt;</span> <span class="kw1">struct</span> <span class="coMULTI">/*inner-iterator*/</span><span class="sy4">;</span>           <span class="co1">// exposition only</span>
 
  <span class="kw1">public</span><span class="sy4">:</span>
    lazy_split_view<span class="br0">(</span><span class="br0">)</span>
      requires default_initializable<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> default_initializable<span class="sy1">&lt;</span>Pattern<span class="sy1">&gt;</span> <span class="sy1">=</span> <span class="kw1">default</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> lazy_split_view<span class="br0">(</span>V base, Pattern pattern<span class="br0">)</span><span class="sy4">;</span>
 
    <span class="kw1">template</span><span class="sy1">&lt;</span>input_range R<span class="sy1">&gt;</span>
      requires constructible_from<span class="sy1">&lt;</span>V, <a href="../ranges/all_view.html"><span class="kw2919">views::<span class="me2">all_t</span></span></a><span class="sy1">&lt;</span>R<span class="sy1">&gt;&gt;</span> <span class="sy3">&amp;&amp;</span>
               constructible_from<span class="sy1">&lt;</span>Pattern, single_view<span class="sy1">&lt;</span>range_value_t<span class="sy1">&lt;</span>R<span class="sy1">&gt;&gt;&gt;</span>
    <span class="kw4">constexpr</span> lazy_split_view<span class="br0">(</span>R<span class="sy3">&amp;&amp;</span> r, range_value_t<span class="sy1">&lt;</span>R<span class="sy1">&gt;</span> e<span class="br0">)</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> V base<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span><span class="sy3">&amp;</span> requires copy_constructible<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> <span class="br0">{</span> <span class="kw1">return</span> base_<span class="sy4">;</span> <span class="br0">}</span>
    <span class="kw4">constexpr</span> V base<span class="br0">(</span><span class="br0">)</span> <span class="sy3">&amp;&amp;</span> <span class="br0">{</span> <span class="kw1">return</span> std<span class="sy4">::</span><span class="me2">move</span><span class="br0">(</span>base_<span class="br0">)</span><span class="sy4">;</span> <span class="br0">}</span>
 
    <span class="kw4">constexpr</span> <span class="kw4">auto</span> begin<span class="br0">(</span><span class="br0">)</span> <span class="br0">{</span>
      <span class="kw1">if</span> <span class="kw4">constexpr</span> <span class="br0">(</span>forward_range<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span><span class="br0">)</span> <span class="br0">{</span>
        <span class="kw1">return</span> <span class="coMULTI">/*outer-iterator*/</span><span class="sy1">&lt;</span><span class="coMULTI">/*simple-view*/</span><span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> <span class="coMULTI">/*simple-view*/</span><span class="sy1">&lt;</span>Pattern<span class="sy1">&gt;&gt;</span>
          <span class="br0">{</span><span class="sy2">*</span>this, <a href="../../../http:/en.cppreference.com/w/cpp/ranges-ranges-placeholder/begin"><span class="kw2885">ranges::<span class="me2">begin</span></span></a><span class="br0">(</span>base_<span class="br0">)</span><span class="br0">}</span><span class="sy4">;</span>
      <span class="br0">}</span> <span class="kw1">else</span> <span class="br0">{</span>
        current_ <span class="sy1">=</span> <a href="../../../http:/en.cppreference.com/w/cpp/ranges-ranges-placeholder/begin"><span class="kw2885">ranges::<span class="me2">begin</span></span></a><span class="br0">(</span>base_<span class="br0">)</span><span class="sy4">;</span>
        <span class="kw1">return</span> <span class="coMULTI">/*outer-iterator*/</span><span class="sy1">&lt;</span><span class="kw2">false</span><span class="sy1">&gt;</span><span class="br0">{</span><span class="sy2">*</span>this<span class="br0">}</span><span class="sy4">;</span>
      <span class="br0">}</span>
    <span class="br0">}</span>
 
    <span class="kw4">constexpr</span> <span class="kw4">auto</span> begin<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span> requires forward_range<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> forward_range<span class="sy1">&lt;</span><span class="kw4">const</span> V<span class="sy1">&gt;</span> <span class="br0">{</span>
      <span class="kw1">return</span> <span class="coMULTI">/*outer-iterator*/</span><span class="sy1">&lt;</span><span class="kw2">true</span><span class="sy1">&gt;</span><span class="br0">{</span><span class="sy2">*</span>this, <a href="../../../http:/en.cppreference.com/w/cpp/ranges-ranges-placeholder/begin"><span class="kw2885">ranges::<span class="me2">begin</span></span></a><span class="br0">(</span>base_<span class="br0">)</span><span class="br0">}</span><span class="sy4">;</span>
    <span class="br0">}</span>
 
    <span class="kw4">constexpr</span> <span class="kw4">auto</span> end<span class="br0">(</span><span class="br0">)</span> requires forward_range<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> common_range<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> <span class="br0">{</span>
      <span class="kw1">return</span> <span class="coMULTI">/*outer-iterator*/</span><span class="sy1">&lt;</span><span class="coMULTI">/*simple-view*/</span><span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> <span class="coMULTI">/*simple-view*/</span><span class="sy1">&lt;</span>Pattern<span class="sy1">&gt;&gt;</span>
        <span class="br0">{</span><span class="sy2">*</span>this, <a href="../../../http:/en.cppreference.com/w/cpp/ranges-ranges-placeholder/end"><span class="kw2887">ranges::<span class="me2">end</span></span></a><span class="br0">(</span>base_<span class="br0">)</span><span class="br0">}</span><span class="sy4">;</span>
    <span class="br0">}</span>
 
    <span class="kw4">constexpr</span> <span class="kw4">auto</span> end<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span> <span class="br0">{</span>
      <span class="kw1">if</span> <span class="kw4">constexpr</span> <span class="br0">(</span>forward_range<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> forward_range<span class="sy1">&lt;</span><span class="kw4">const</span> V<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> common_range<span class="sy1">&lt;</span><span class="kw4">const</span> V<span class="sy1">&gt;</span><span class="br0">)</span>
        <span class="kw1">return</span> <span class="coMULTI">/*outer-iterator*/</span><span class="sy1">&lt;</span><span class="kw2">true</span><span class="sy1">&gt;</span><span class="br0">{</span><span class="sy2">*</span>this, <a href="../../../http:/en.cppreference.com/w/cpp/ranges-ranges-placeholder/end"><span class="kw2887">ranges::<span class="me2">end</span></span></a><span class="br0">(</span>base_<span class="br0">)</span><span class="br0">}</span><span class="sy4">;</span>
      <span class="kw1">else</span>
        <span class="kw1">return</span> default_sentinel<span class="sy4">;</span>
    <span class="br0">}</span>
  <span class="br0">}</span><span class="sy4">;</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> R, <span class="kw1">class</span> P<span class="sy1">&gt;</span>
    lazy_split_view<span class="br0">(</span>R<span class="sy3">&amp;&amp;</span>, P<span class="sy3">&amp;&amp;</span><span class="br0">)</span> <span class="sy2">-</span><span class="sy1">&gt;</span> lazy_split_view<span class="sy1">&lt;</span><a href="../ranges/all_view.html"><span class="kw2919">views::<span class="me2">all_t</span></span></a><span class="sy1">&lt;</span>R<span class="sy1">&gt;</span>, <a href="../ranges/all_view.html"><span class="kw2919">views::<span class="me2">all_t</span></span></a><span class="sy1">&lt;</span>P<span class="sy1">&gt;&gt;</span><span class="sy4">;</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span>input_range R<span class="sy1">&gt;</span>
    lazy_split_view<span class="br0">(</span>R<span class="sy3">&amp;&amp;</span>, range_value_t<span class="sy1">&lt;</span>R<span class="sy1">&gt;</span><span class="br0">)</span>
      <span class="sy2">-</span><span class="sy1">&gt;</span> lazy_split_view<span class="sy1">&lt;</span><a href="../ranges/all_view.html"><span class="kw2919">views::<span class="me2">all_t</span></span></a><span class="sy1">&lt;</span>R<span class="sy1">&gt;</span>, single_view<span class="sy1">&lt;</span>range_value_t<span class="sy1">&lt;</span>R<span class="sy1">&gt;&gt;&gt;</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<h4><span class="mw-headline" id="Class_template_std::ranges::lazy_split_view::outer_iterator">Class template <span class="t-lc">std::ranges::lazy_split_view::outer_iterator</span></span></h4>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">namespace</span> std<span class="sy4">::</span><span class="me2">ranges</span> <span class="br0">{</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span>input_range V, forward_range Pattern<span class="sy1">&gt;</span>
    requires view<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> view<span class="sy1">&lt;</span>Pattern<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
             indirectly_comparable<span class="sy1">&lt;</span>iterator_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span>, iterator_t<span class="sy1">&lt;</span>Pattern<span class="sy1">&gt;</span>, <a href="../functional/ranges/equal_to.html"><span class="kw2844">ranges::<span class="me2">equal_to</span></span></a><span class="sy1">&gt;</span>
             <span class="sy3">&amp;&amp;</span> <span class="br0">(</span>forward_range<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> <span class="sy3">||</span> <span class="coMULTI">/*tiny-range*/</span><span class="sy1">&lt;</span>Pattern<span class="sy1">&gt;</span><span class="br0">)</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw4">bool</span> Const<span class="sy1">&gt;</span>
  <span class="kw1">struct</span> lazy_split_view<span class="sy1">&lt;</span>V, Pattern<span class="sy1">&gt;</span><span class="sy4">::</span><span class="coMULTI">/*outer-iterator*/</span> <span class="br0">{</span>
  <span class="kw1">private</span><span class="sy4">:</span>
    <span class="kw1">using</span> Parent <span class="sy1">=</span> <span class="coMULTI">/*maybe-const*/</span><span class="sy1">&lt;</span>Const, lazy_split_view<span class="sy1">&gt;</span><span class="sy4">;</span> <span class="co1">// exposition only</span>
    <span class="kw1">using</span> Base <span class="sy1">=</span> <span class="coMULTI">/*maybe-const*/</span><span class="sy1">&lt;</span>Const, V<span class="sy1">&gt;</span><span class="sy4">;</span>                 <span class="co1">// exposition only</span>
    Parent<span class="sy2">*</span> parent_ <span class="sy1">=</span> nullptr<span class="sy4">;</span>                              <span class="co1">// exposition only</span>
 
    iterator_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span> current_ <span class="sy1">=</span> iterator_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span><span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>      <span class="co1">// exposition only, present only</span>
                                                         <span class="co1">// if V models forward_range</span>
 
    <span class="kw4">bool</span> trailing_empty_ <span class="sy1">=</span> <span class="kw2">false</span><span class="sy4">;</span>                        <span class="co1">// exposition only</span>
 
  <span class="kw1">public</span><span class="sy4">:</span>
    <span class="kw1">using</span> iterator_concept  <span class="sy1">=</span>
      conditional_t<span class="sy1">&lt;</span>forward_range<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span>, forward_iterator_tag, input_iterator_tag<span class="sy1">&gt;</span><span class="sy4">;</span>
 
    <span class="kw1">using</span> iterator_category <span class="sy1">=</span> input_iterator_tag<span class="sy4">;</span>        <span class="co1">// present only if Base</span>
                                                         <span class="co1">// models forward_range</span>
 
    <span class="co1">// class lazy_split_view::/*outer-iterator*/::value_type</span>
    <span class="kw1">struct</span> value_type<span class="sy4">;</span>
    <span class="kw1">using</span> difference_type   <span class="sy1">=</span> range_difference_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span><span class="sy4">;</span>
 
    <span class="coMULTI">/*outer-iterator*/</span><span class="br0">(</span><span class="br0">)</span> <span class="sy1">=</span> <span class="kw1">default</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> <span class="kw1">explicit</span> <span class="coMULTI">/*outer-iterator*/</span><span class="br0">(</span>Parent<span class="sy3">&amp;</span> parent<span class="br0">)</span>
      requires <span class="br0">(</span><span class="sy3">!</span>forward_range<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span><span class="br0">)</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> <span class="coMULTI">/*outer-iterator*/</span><span class="br0">(</span>Parent<span class="sy3">&amp;</span> parent, iterator_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span> current<span class="br0">)</span>
      requires forward_range<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> <span class="coMULTI">/*outer-iterator*/</span><span class="br0">(</span><span class="coMULTI">/*outer-iterator*/</span><span class="sy1">&lt;</span><span class="sy3">!</span>Const<span class="sy1">&gt;</span> i<span class="br0">)</span>
      requires Const <span class="sy3">&amp;&amp;</span> convertible_to<span class="sy1">&lt;</span>iterator_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span>, iterator_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;&gt;</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> value_type operator<span class="sy2">*</span><span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> <span class="coMULTI">/*outer-iterator*/</span><span class="sy3">&amp;</span> operator<span class="sy2">++</span><span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> decltype<span class="br0">(</span><span class="kw4">auto</span><span class="br0">)</span> operator<span class="sy2">++</span><span class="br0">(</span><span class="kw4">int</span><span class="br0">)</span> <span class="br0">{</span>
      <span class="kw1">if</span> <span class="kw4">constexpr</span> <span class="br0">(</span>forward_range<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span><span class="br0">)</span> <span class="br0">{</span>
        <span class="kw4">auto</span> tmp <span class="sy1">=</span> <span class="sy2">*</span>this<span class="sy4">;</span>
        <span class="sy2">++*</span>this<span class="sy4">;</span>
        <span class="kw1">return</span> tmp<span class="sy4">;</span>
      <span class="br0">}</span> <span class="kw1">else</span>
        <span class="sy2">++*</span>this<span class="sy4">;</span>
    <span class="br0">}</span>
 
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> operator<span class="sy1">==</span><span class="br0">(</span><span class="kw4">const</span> <span class="coMULTI">/*outer-iterator*/</span><span class="sy3">&amp;</span> x,
                                     <span class="kw4">const</span> <span class="coMULTI">/*outer-iterator*/</span><span class="sy3">&amp;</span> y<span class="br0">)</span>
      requires forward_range<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span><span class="sy4">;</span>
 
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> operator<span class="sy1">==</span><span class="br0">(</span><span class="kw4">const</span> <span class="coMULTI">/*outer-iterator*/</span><span class="sy3">&amp;</span> x, default_sentinel_t<span class="br0">)</span><span class="sy4">;</span>
  <span class="br0">}</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<h4><span class="mw-headline" id="Class_std::ranges::lazy_split_view::outer_iterator::value_type">Class <span class="t-lc">std::ranges::lazy_split_view::outer_iterator::value_type</span></span></h4>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">namespace</span> std<span class="sy4">::</span><span class="me2">ranges</span> <span class="br0">{</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span>input_range V, forward_range Pattern<span class="sy1">&gt;</span>
    requires view<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> view<span class="sy1">&lt;</span>Pattern<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
             indirectly_comparable<span class="sy1">&lt;</span>iterator_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span>, iterator_t<span class="sy1">&lt;</span>Pattern<span class="sy1">&gt;</span>, <a href="../functional/ranges/equal_to.html"><span class="kw2844">ranges::<span class="me2">equal_to</span></span></a><span class="sy1">&gt;</span>
             <span class="sy3">&amp;&amp;</span> <span class="br0">(</span>forward_range<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> <span class="sy3">||</span> <span class="coMULTI">/*tiny-range*/</span><span class="sy1">&lt;</span>Pattern<span class="sy1">&gt;</span><span class="br0">)</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw4">bool</span> Const<span class="sy1">&gt;</span>
  <span class="kw1">struct</span> lazy_split_view<span class="sy1">&lt;</span>V, Pattern<span class="sy1">&gt;</span><span class="sy4">::</span><span class="coMULTI">/*outer-iterator*/</span><span class="sy1">&lt;</span>Const<span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">value_type</span>
    <span class="sy4">:</span> view_interface<span class="sy1">&lt;</span>value_type<span class="sy1">&gt;</span> <span class="br0">{</span>
  <span class="kw1">private</span><span class="sy4">:</span>
    <span class="coMULTI">/*outer-iterator*/</span> i_ <span class="sy1">=</span> <span class="coMULTI">/*outer-iterator*/</span><span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>               <span class="co1">// exposition only</span>
  <span class="kw1">public</span><span class="sy4">:</span>
    value_type<span class="br0">(</span><span class="br0">)</span> <span class="sy1">=</span> <span class="kw1">default</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> <span class="kw1">explicit</span> value_type<span class="br0">(</span><span class="coMULTI">/*outer-iterator*/</span> i<span class="br0">)</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> <span class="coMULTI">/*inner-iterator*/</span><span class="sy1">&lt;</span>Const<span class="sy1">&gt;</span> begin<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> default_sentinel_t end<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span> <span class="kw1">noexcept</span><span class="sy4">;</span>
  <span class="br0">}</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<h4><span class="mw-headline" id="Class_template_std::ranges::lazy_split_view::inner_iterator">Class template <span class="t-lc">std::ranges::lazy_split_view::inner_iterator</span></span></h4>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">namespace</span> std<span class="sy4">::</span><span class="me2">ranges</span> <span class="br0">{</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span>input_range V, forward_range Pattern<span class="sy1">&gt;</span>
    requires view<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> view<span class="sy1">&lt;</span>Pattern<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
             indirectly_comparable<span class="sy1">&lt;</span>iterator_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span>, iterator_t<span class="sy1">&lt;</span>Pattern<span class="sy1">&gt;</span>, <a href="../functional/ranges/equal_to.html"><span class="kw2844">ranges::<span class="me2">equal_to</span></span></a><span class="sy1">&gt;</span>
             <span class="sy3">&amp;&amp;</span> <span class="br0">(</span>forward_range<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> <span class="sy3">||</span> <span class="coMULTI">/*tiny-range*/</span><span class="sy1">&lt;</span>Pattern<span class="sy1">&gt;</span><span class="br0">)</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw4">bool</span> Const<span class="sy1">&gt;</span>
  <span class="kw1">struct</span> lazy_split_view<span class="sy1">&lt;</span>V, Pattern<span class="sy1">&gt;</span><span class="sy4">::</span><span class="coMULTI">/*inner-iterator*/</span> <span class="br0">{</span>
  <span class="kw1">private</span><span class="sy4">:</span>
    <span class="kw1">using</span> Base <span class="sy1">=</span> <span class="coMULTI">/*maybe-const*/</span><span class="sy1">&lt;</span>Const, V<span class="sy1">&gt;</span><span class="sy4">;</span>                     <span class="co1">// exposition only</span>
    <span class="coMULTI">/*outer-iterator*/</span><span class="sy1">&lt;</span>Const<span class="sy1">&gt;</span> i_ <span class="sy1">=</span> <span class="coMULTI">/*outer-iterator*/</span><span class="sy1">&lt;</span>Const<span class="sy1">&gt;</span><span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span> <span class="co1">// exposition only</span>
    <span class="kw4">bool</span> incremented_ <span class="sy1">=</span> <span class="kw2">false</span><span class="sy4">;</span>                                  <span class="co1">// exposition only</span>
 
  <span class="kw1">public</span><span class="sy4">:</span>
    <span class="kw1">using</span> iterator_concept  <span class="sy1">=</span> <span class="kw1">typename</span> <span class="coMULTI">/*outer-iterator*/</span><span class="sy1">&lt;</span>Const<span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">iterator_concept</span><span class="sy4">;</span>
 
    <span class="kw1">using</span> iterator_category <span class="sy1">=</span> <span class="coMULTI">/* see description */</span><span class="sy4">;</span>        <span class="co1">// present only if Base</span>
                                                            <span class="co1">// models forward_range</span>
    <span class="kw1">using</span> value_type        <span class="sy1">=</span> range_value_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span><span class="sy4">;</span>
    <span class="kw1">using</span> difference_type   <span class="sy1">=</span> range_difference_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span><span class="sy4">;</span>
 
    <span class="coMULTI">/*inner-iterator*/</span><span class="br0">(</span><span class="br0">)</span> <span class="sy1">=</span> <span class="kw1">default</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> <span class="kw1">explicit</span> <span class="coMULTI">/*inner-iterator*/</span><span class="br0">(</span><span class="coMULTI">/*outer-iterator*/</span><span class="sy1">&lt;</span>Const<span class="sy1">&gt;</span> i<span class="br0">)</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> <span class="kw4">const</span> iterator_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span><span class="sy3">&amp;</span> base<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span> <span class="sy3">&amp;</span> <span class="kw1">noexcept</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> iterator_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span> base<span class="br0">(</span><span class="br0">)</span> <span class="sy3">&amp;&amp;</span> requires forward_range<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> decltype<span class="br0">(</span><span class="kw4">auto</span><span class="br0">)</span> operator<span class="sy2">*</span><span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span> <span class="br0">{</span> <span class="kw1">return</span> <span class="sy2">*</span>i_.<span class="me1">current</span><span class="sy4">;</span> <span class="br0">}</span>
 
    <span class="kw4">constexpr</span> <span class="coMULTI">/*inner-iterator*/</span><span class="sy3">&amp;</span> operator<span class="sy2">++</span><span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> decltype<span class="br0">(</span><span class="kw4">auto</span><span class="br0">)</span> operator<span class="sy2">++</span><span class="br0">(</span><span class="kw4">int</span><span class="br0">)</span> <span class="br0">{</span>
      <span class="kw1">if</span> <span class="kw4">constexpr</span> <span class="br0">(</span>forward_range<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span><span class="br0">)</span> <span class="br0">{</span>
        <span class="kw4">auto</span> tmp <span class="sy1">=</span> <span class="sy2">*</span>this<span class="sy4">;</span>
        <span class="sy2">++*</span>this<span class="sy4">;</span>
        <span class="kw1">return</span> tmp<span class="sy4">;</span>
      <span class="br0">}</span> <span class="kw1">else</span>
        <span class="sy2">++*</span>this<span class="sy4">;</span>
    <span class="br0">}</span>
 
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> operator<span class="sy1">==</span><span class="br0">(</span><span class="kw4">const</span> <span class="coMULTI">/*inner-iterator*/</span><span class="sy3">&amp;</span> x,
                                     <span class="kw4">const</span> <span class="coMULTI">/*inner-iterator*/</span><span class="sy3">&amp;</span> y<span class="br0">)</span>
      requires forward_range<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span><span class="sy4">;</span>
 
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> operator<span class="sy1">==</span><span class="br0">(</span><span class="kw4">const</span> <span class="coMULTI">/*inner-iterator*/</span><span class="sy3">&amp;</span> x, default_sentinel_t<span class="br0">)</span><span class="sy4">;</span>
 
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> decltype<span class="br0">(</span><span class="kw4">auto</span><span class="br0">)</span> iter_move<span class="br0">(</span><span class="kw4">const</span> <span class="coMULTI">/*inner-iterator*/</span><span class="sy3">&amp;</span> i<span class="br0">)</span>
    <span class="kw1">noexcept</span><span class="br0">(</span><span class="kw1">noexcept</span><span class="br0">(</span><a href="../iterator/ranges/iter_move.html"><span class="kw3143">ranges::<span class="me2">iter_move</span></span></a><span class="br0">(</span>i.<span class="me1">i_</span>.<span class="me1">current</span><span class="br0">)</span><span class="br0">)</span><span class="br0">)</span> <span class="br0">{</span>
      <span class="kw1">return</span> <a href="../iterator/ranges/iter_move.html"><span class="kw3143">ranges::<span class="me2">iter_move</span></span></a><span class="br0">(</span>i.<span class="me1">i_</span>.<span class="me1">current</span><span class="br0">)</span><span class="sy4">;</span>
    <span class="br0">}</span>
 
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> <span class="kw4">void</span> iter_swap<span class="br0">(</span><span class="kw4">const</span> <span class="coMULTI">/*inner-iterator*/</span><span class="sy3">&amp;</span> x,
                                    <span class="kw4">const</span> <span class="coMULTI">/*inner-iterator*/</span><span class="sy3">&amp;</span> y<span class="br0">)</span>
      <span class="kw1">noexcept</span><span class="br0">(</span><span class="kw1">noexcept</span><span class="br0">(</span><a href="../iterator/ranges/iter_swap.html"><span class="kw3278">ranges::<span class="me2">iter_swap</span></span></a><span class="br0">(</span>x.<span class="me1">i_</span>.<span class="me1">current</span>, y.<span class="me1">i_</span>.<span class="me1">current</span><span class="br0">)</span><span class="br0">)</span><span class="br0">)</span>
      requires indirectly_swappable<span class="sy1">&lt;</span>iterator_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;&gt;</span><span class="sy4">;</span>
  <span class="br0">}</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<h4><span class="mw-headline" id="Class_template_std::ranges::split_view">Class template <span class="t-lc">std::ranges::split_view</span></span></h4>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">namespace</span> std<span class="sy4">::</span><span class="me2">ranges</span> <span class="br0">{</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span>forward_range V, forward_range Pattern<span class="sy1">&gt;</span>
    requires view<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> view<span class="sy1">&lt;</span>Pattern<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
             indirectly_comparable<span class="sy1">&lt;</span>iterator_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span>, iterator_t<span class="sy1">&lt;</span>Pattern<span class="sy1">&gt;</span>, <a href="../functional/ranges/equal_to.html"><span class="kw2844">ranges::<span class="me2">equal_to</span></span></a><span class="sy1">&gt;</span>
  <span class="kw1">class</span> split_view <span class="sy4">:</span> <span class="kw1">public</span> view_interface<span class="sy1">&lt;</span>split_view<span class="sy1">&lt;</span>V, Pattern<span class="sy1">&gt;&gt;</span> <span class="br0">{</span>
  <span class="kw1">private</span><span class="sy4">:</span>
    V base_ <span class="sy1">=</span> V<span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>                              <span class="co1">// exposition only</span>
    Pattern pattern_ <span class="sy1">=</span> Pattern<span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>               <span class="co1">// exposition only</span>
 
    <span class="co1">// class split_view::iterator</span>
    <span class="kw1">struct</span> iterator<span class="sy4">;</span>                            <span class="co1">// exposition only</span>
 
    <span class="co1">// class split_view::sentinel</span>
    <span class="kw1">struct</span> sentinel<span class="sy4">;</span>                            <span class="co1">// exposition only</span>
 
  <span class="kw1">public</span><span class="sy4">:</span>
    split_view<span class="br0">(</span><span class="br0">)</span>
      requires default_initializable<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> default_initializable<span class="sy1">&lt;</span>Pattern<span class="sy1">&gt;</span> <span class="sy1">=</span> <span class="kw1">default</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> split_view<span class="br0">(</span>V base, Pattern pattern<span class="br0">)</span><span class="sy4">;</span>
 
    <span class="kw1">template</span><span class="sy1">&lt;</span>forward_range R<span class="sy1">&gt;</span>
      requires constructible_from<span class="sy1">&lt;</span>V, <a href="../ranges/all_view.html"><span class="kw2919">views::<span class="me2">all_t</span></span></a><span class="sy1">&lt;</span>R<span class="sy1">&gt;&gt;</span> <span class="sy3">&amp;&amp;</span>
               constructible_from<span class="sy1">&lt;</span>Pattern, single_view<span class="sy1">&lt;</span>range_value_t<span class="sy1">&lt;</span>R<span class="sy1">&gt;&gt;&gt;</span>
    <span class="kw4">constexpr</span> split_view<span class="br0">(</span>R<span class="sy3">&amp;&amp;</span> r, range_value_t<span class="sy1">&lt;</span>R<span class="sy1">&gt;</span> e<span class="br0">)</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> V base<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span><span class="sy3">&amp;</span> requires copy_constructible<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> <span class="br0">{</span> <span class="kw1">return</span> base_<span class="sy4">;</span> <span class="br0">}</span>
    <span class="kw4">constexpr</span> V base<span class="br0">(</span><span class="br0">)</span> <span class="sy3">&amp;&amp;</span> <span class="br0">{</span> <span class="kw1">return</span> std<span class="sy4">::</span><span class="me2">move</span><span class="br0">(</span>base_<span class="br0">)</span><span class="sy4">;</span> <span class="br0">}</span>
 
    <span class="kw4">constexpr</span> iterator begin<span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> <span class="kw4">auto</span> end<span class="br0">(</span><span class="br0">)</span> <span class="br0">{</span>
      <span class="kw1">if</span> <span class="kw4">constexpr</span> <span class="br0">(</span>common_range<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span><span class="br0">)</span> <span class="br0">{</span>
        <span class="kw1">return</span> iterator<span class="br0">{</span><span class="sy2">*</span>this, <a href="../../../http:/en.cppreference.com/w/cpp/ranges-ranges-placeholder/end"><span class="kw2887">ranges::<span class="me2">end</span></span></a><span class="br0">(</span>base_<span class="br0">)</span>, <span class="br0">{</span><span class="br0">}</span> <span class="br0">}</span><span class="sy4">;</span>
      <span class="br0">}</span> <span class="kw1">else</span> <span class="br0">{</span>
        <span class="kw1">return</span> sentinel<span class="br0">{</span><span class="sy2">*</span>this<span class="br0">}</span><span class="sy4">;</span>
      <span class="br0">}</span>
    <span class="br0">}</span>
 
    <span class="kw4">constexpr</span> subrange<span class="sy1">&lt;</span>iterator_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;&gt;</span> <span class="coMULTI">/*find-next*/</span><span class="br0">(</span>iterator_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span><span class="br0">)</span><span class="sy4">;</span> <span class="co1">// exposition only</span>
  <span class="br0">}</span><span class="sy4">;</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> R, <span class="kw1">class</span> P<span class="sy1">&gt;</span>
    split_view<span class="br0">(</span>R<span class="sy3">&amp;&amp;</span>, P<span class="sy3">&amp;&amp;</span><span class="br0">)</span> <span class="sy2">-</span><span class="sy1">&gt;</span> split_view<span class="sy1">&lt;</span><a href="../ranges/all_view.html"><span class="kw2919">views::<span class="me2">all_t</span></span></a><span class="sy1">&lt;</span>R<span class="sy1">&gt;</span>, <a href="../ranges/all_view.html"><span class="kw2919">views::<span class="me2">all_t</span></span></a><span class="sy1">&lt;</span>P<span class="sy1">&gt;&gt;</span><span class="sy4">;</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span>forward_range R<span class="sy1">&gt;</span>
    split_view<span class="br0">(</span>R<span class="sy3">&amp;&amp;</span>, range_value_t<span class="sy1">&lt;</span>R<span class="sy1">&gt;</span><span class="br0">)</span>
      <span class="sy2">-</span><span class="sy1">&gt;</span> split_view<span class="sy1">&lt;</span><a href="../ranges/all_view.html"><span class="kw2919">views::<span class="me2">all_t</span></span></a><span class="sy1">&lt;</span>R<span class="sy1">&gt;</span>, single_view<span class="sy1">&lt;</span>range_value_t<span class="sy1">&lt;</span>R<span class="sy1">&gt;&gt;&gt;</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<h4><span class="mw-headline" id="Class_template_std::ranges::split_view::iterator">Class template <span class="t-lc">std::ranges::split_view::iterator</span></span></h4>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">namespace</span> std<span class="sy4">::</span><span class="me2">ranges</span> <span class="br0">{</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span>forward_range V, forward_range Pattern<span class="sy1">&gt;</span>
    requires view<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> view<span class="sy1">&lt;</span>Pattern<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
             indirectly_comparable<span class="sy1">&lt;</span>iterator_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span>, iterator_t<span class="sy1">&lt;</span>Pattern<span class="sy1">&gt;</span>, <a href="../functional/ranges/equal_to.html"><span class="kw2844">ranges::<span class="me2">equal_to</span></span></a><span class="sy1">&gt;</span>
  <span class="kw1">class</span> split_view<span class="sy1">&lt;</span>V, Pattern<span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">iterator</span> <span class="br0">{</span>
  <span class="kw1">private</span><span class="sy4">:</span>
    split_view<span class="sy2">*</span> parent_ <span class="sy1">=</span> nullptr<span class="sy4">;</span>                              <span class="co1">// exposition only</span>
    iterator_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> cur_ <span class="sy1">=</span> iterator_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span><span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>                       <span class="co1">// exposition only</span>
    subrange<span class="sy1">&lt;</span>iterator_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;&gt;</span> next_ <span class="sy1">=</span> subrange<span class="sy1">&lt;</span>iterator_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;&gt;</span><span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>  <span class="co1">// exposition only</span>
    <span class="kw4">bool</span> trailing_empty_ <span class="sy1">=</span> <span class="kw2">false</span><span class="sy4">;</span>                               <span class="co1">// exposition only</span>
 
  <span class="kw1">public</span><span class="sy4">:</span>
    <span class="kw1">using</span> iterator_concept <span class="sy1">=</span> forward_iterator_tag<span class="sy4">;</span>
    <span class="kw1">using</span> iterator_category <span class="sy1">=</span> input_iterator_tag<span class="sy4">;</span>
    <span class="kw1">using</span> value_type <span class="sy1">=</span> subrange<span class="sy1">&lt;</span>iterator_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;&gt;</span><span class="sy4">;</span>
    <span class="kw1">using</span> difference_type <span class="sy1">=</span> range_difference_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span><span class="sy4">;</span>
 
    iterator<span class="br0">(</span><span class="br0">)</span> <span class="sy1">=</span> <span class="kw1">default</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> iterator<span class="br0">(</span>split_view<span class="sy3">&amp;</span> parent, iterator_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> current,
                       subrange<span class="sy1">&lt;</span>iterator_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;&gt;</span> next<span class="br0">)</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> iterator_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> base<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> value_type operator<span class="sy2">*</span><span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> iterator<span class="sy3">&amp;</span> operator<span class="sy2">++</span><span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> iterator operator<span class="sy2">++</span><span class="br0">(</span><span class="kw4">int</span><span class="br0">)</span><span class="sy4">;</span>
 
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> operator<span class="sy1">==</span><span class="br0">(</span><span class="kw4">const</span> iterator<span class="sy3">&amp;</span> x, <span class="kw4">const</span> iterator<span class="sy3">&amp;</span> y<span class="br0">)</span><span class="sy4">;</span>
  <span class="br0">}</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<h4><span class="mw-headline" id="Class_template_std::ranges::split_view::sentinel">Class template <span class="t-lc">std::ranges::split_view::sentinel</span></span></h4>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">namespace</span> std<span class="sy4">::</span><span class="me2">ranges</span> <span class="br0">{</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span>forward_range V, forward_range Pattern<span class="sy1">&gt;</span>
    requires view<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> view<span class="sy1">&lt;</span>Pattern<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
             indirectly_comparable<span class="sy1">&lt;</span>iterator_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span>, iterator_t<span class="sy1">&lt;</span>Pattern<span class="sy1">&gt;</span>, <a href="../functional/ranges/equal_to.html"><span class="kw2844">ranges::<span class="me2">equal_to</span></span></a><span class="sy1">&gt;</span>
  <span class="kw1">struct</span> split_view<span class="sy1">&lt;</span>V, Pattern<span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">sentinel</span> <span class="br0">{</span>
  <span class="kw1">private</span><span class="sy4">:</span>
    sentinel_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> end_ <span class="sy1">=</span> sentinel_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span><span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>               <span class="co1">// exposition only</span>
 
  <span class="kw1">public</span><span class="sy4">:</span>
    sentinel<span class="br0">(</span><span class="br0">)</span> <span class="sy1">=</span> <span class="kw1">default</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> <span class="kw1">explicit</span> sentinel<span class="br0">(</span>split_view<span class="sy3">&amp;</span> parent<span class="br0">)</span><span class="sy4">;</span>
 
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> operator<span class="sy1">==</span><span class="br0">(</span><span class="kw4">const</span> iterator<span class="sy3">&amp;</span> x, <span class="kw4">const</span> sentinel<span class="sy3">&amp;</span> y<span class="br0">)</span><span class="sy4">;</span>
  <span class="br0">}</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<h4><span class="mw-headline" id="Class_template_std::ranges::common_view">Class template <span class="t-lc">std::ranges::common_view</span></span></h4>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">namespace</span> std<span class="sy4">::</span><span class="me2">ranges</span> <span class="br0">{</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span>view V<span class="sy1">&gt;</span>
    requires <span class="br0">(</span><span class="sy3">!</span>common_range<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> copyable<span class="sy1">&lt;</span>iterator_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;&gt;</span><span class="br0">)</span>
  <span class="kw1">class</span> common_view <span class="sy4">:</span> <span class="kw1">public</span> view_interface<span class="sy1">&lt;</span>common_view<span class="sy1">&lt;</span>V<span class="sy1">&gt;&gt;</span> <span class="br0">{</span>
  <span class="kw1">private</span><span class="sy4">:</span>
    V base_ <span class="sy1">=</span> V<span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>  <span class="co1">// exposition only</span>
  <span class="kw1">public</span><span class="sy4">:</span>
    common_view<span class="br0">(</span><span class="br0">)</span> requires default_initializable<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> <span class="sy1">=</span> <span class="kw1">default</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> <span class="kw1">explicit</span> common_view<span class="br0">(</span>V r<span class="br0">)</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> V base<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span><span class="sy3">&amp;</span> requires copy_constructible<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> <span class="br0">{</span> <span class="kw1">return</span> base_<span class="sy4">;</span> <span class="br0">}</span>
    <span class="kw4">constexpr</span> V base<span class="br0">(</span><span class="br0">)</span> <span class="sy3">&amp;&amp;</span> <span class="br0">{</span> <span class="kw1">return</span> std<span class="sy4">::</span><span class="me2">move</span><span class="br0">(</span>base_<span class="br0">)</span><span class="sy4">;</span> <span class="br0">}</span>
 
    <span class="kw4">constexpr</span> <span class="kw4">auto</span> begin<span class="br0">(</span><span class="br0">)</span> <span class="br0">{</span>
      <span class="kw1">if</span> <span class="kw4">constexpr</span> <span class="br0">(</span>random_access_range<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> sized_range<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span><span class="br0">)</span>
        <span class="kw1">return</span> <a href="../../../http:/en.cppreference.com/w/cpp/ranges-ranges-placeholder/begin"><span class="kw2885">ranges::<span class="me2">begin</span></span></a><span class="br0">(</span>base_<span class="br0">)</span><span class="sy4">;</span>
      <span class="kw1">else</span>
        <span class="kw1">return</span> common_iterator<span class="sy1">&lt;</span>iterator_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span>, sentinel_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;&gt;</span><span class="br0">(</span><a href="../../../http:/en.cppreference.com/w/cpp/ranges-ranges-placeholder/begin"><span class="kw2885">ranges::<span class="me2">begin</span></span></a><span class="br0">(</span>base_<span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
    <span class="br0">}</span>
 
    <span class="kw4">constexpr</span> <span class="kw4">auto</span> begin<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span> requires range<span class="sy1">&lt;</span><span class="kw4">const</span> V<span class="sy1">&gt;</span> <span class="br0">{</span>
      <span class="kw1">if</span> <span class="kw4">constexpr</span> <span class="br0">(</span>random_access_range<span class="sy1">&lt;</span><span class="kw4">const</span> V<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> sized_range<span class="sy1">&lt;</span><span class="kw4">const</span> V<span class="sy1">&gt;</span><span class="br0">)</span>
        <span class="kw1">return</span> <a href="../../../http:/en.cppreference.com/w/cpp/ranges-ranges-placeholder/begin"><span class="kw2885">ranges::<span class="me2">begin</span></span></a><span class="br0">(</span>base_<span class="br0">)</span><span class="sy4">;</span>
      <span class="kw1">else</span>
        <span class="kw1">return</span> common_iterator<span class="sy1">&lt;</span>iterator_t<span class="sy1">&lt;</span><span class="kw4">const</span> V<span class="sy1">&gt;</span>,
          sentinel_t<span class="sy1">&lt;</span><span class="kw4">const</span> V<span class="sy1">&gt;&gt;</span><span class="br0">(</span><a href="../../../http:/en.cppreference.com/w/cpp/ranges-ranges-placeholder/begin"><span class="kw2885">ranges::<span class="me2">begin</span></span></a><span class="br0">(</span>base_<span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
    <span class="br0">}</span>
 
    <span class="kw4">constexpr</span> <span class="kw4">auto</span> end<span class="br0">(</span><span class="br0">)</span> <span class="br0">{</span>
      <span class="kw1">if</span> <span class="kw4">constexpr</span> <span class="br0">(</span>random_access_range<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> sized_range<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span><span class="br0">)</span>
        <span class="kw1">return</span> <a href="../../../http:/en.cppreference.com/w/cpp/ranges-ranges-placeholder/begin"><span class="kw2885">ranges::<span class="me2">begin</span></span></a><span class="br0">(</span>base_<span class="br0">)</span> <span class="sy2">+</span> <a href="../ranges/size.html"><span class="kw3103">ranges::<span class="me2">size</span></span></a><span class="br0">(</span>base_<span class="br0">)</span><span class="sy4">;</span>
      <span class="kw1">else</span>
        <span class="kw1">return</span> common_iterator<span class="sy1">&lt;</span>iterator_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span>, sentinel_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;&gt;</span><span class="br0">(</span><a href="../../../http:/en.cppreference.com/w/cpp/ranges-ranges-placeholder/end"><span class="kw2887">ranges::<span class="me2">end</span></span></a><span class="br0">(</span>base_<span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
    <span class="br0">}</span>
 
    <span class="kw4">constexpr</span> <span class="kw4">auto</span> end<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span> requires range<span class="sy1">&lt;</span><span class="kw4">const</span> V<span class="sy1">&gt;</span> <span class="br0">{</span>
      <span class="kw1">if</span> <span class="kw4">constexpr</span> <span class="br0">(</span>random_access_range<span class="sy1">&lt;</span><span class="kw4">const</span> V<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> sized_range<span class="sy1">&lt;</span><span class="kw4">const</span> V<span class="sy1">&gt;</span><span class="br0">)</span>
        <span class="kw1">return</span> <a href="../../../http:/en.cppreference.com/w/cpp/ranges-ranges-placeholder/begin"><span class="kw2885">ranges::<span class="me2">begin</span></span></a><span class="br0">(</span>base_<span class="br0">)</span> <span class="sy2">+</span> <a href="../ranges/size.html"><span class="kw3103">ranges::<span class="me2">size</span></span></a><span class="br0">(</span>base_<span class="br0">)</span><span class="sy4">;</span>
      <span class="kw1">else</span>
        <span class="kw1">return</span> common_iterator<span class="sy1">&lt;</span>iterator_t<span class="sy1">&lt;</span><span class="kw4">const</span> V<span class="sy1">&gt;</span>,
          sentinel_t<span class="sy1">&lt;</span><span class="kw4">const</span> V<span class="sy1">&gt;&gt;</span><span class="br0">(</span><a href="../../../http:/en.cppreference.com/w/cpp/ranges-ranges-placeholder/end"><span class="kw2887">ranges::<span class="me2">end</span></span></a><span class="br0">(</span>base_<span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
    <span class="br0">}</span>
 
    <span class="kw4">constexpr</span> <span class="kw4">auto</span> size<span class="br0">(</span><span class="br0">)</span> requires sized_range<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> <span class="br0">{</span>
      <span class="kw1">return</span> <a href="../ranges/size.html"><span class="kw3103">ranges::<span class="me2">size</span></span></a><span class="br0">(</span>base_<span class="br0">)</span><span class="sy4">;</span>
    <span class="br0">}</span>
    <span class="kw4">constexpr</span> <span class="kw4">auto</span> size<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span> requires sized_range<span class="sy1">&lt;</span><span class="kw4">const</span> V<span class="sy1">&gt;</span> <span class="br0">{</span>
      <span class="kw1">return</span> <a href="../ranges/size.html"><span class="kw3103">ranges::<span class="me2">size</span></span></a><span class="br0">(</span>base_<span class="br0">)</span><span class="sy4">;</span>
    <span class="br0">}</span>
  <span class="br0">}</span><span class="sy4">;</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> R<span class="sy1">&gt;</span>
    common_view<span class="br0">(</span>R<span class="sy3">&amp;&amp;</span><span class="br0">)</span> <span class="sy2">-</span><span class="sy1">&gt;</span> common_view<span class="sy1">&lt;</span><a href="../ranges/all_view.html"><span class="kw2919">views::<span class="me2">all_t</span></span></a><span class="sy1">&lt;</span>R<span class="sy1">&gt;&gt;</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<h4><span class="mw-headline" id="Class_template_std::ranges::reverse_view">Class template <span class="t-lc"><a href="../ranges/reverse_view.html" title="cpp/ranges/reverse view">std::ranges::reverse_view</a></span></span></h4>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">namespace</span> std<span class="sy4">::</span><span class="me2">ranges</span> <span class="br0">{</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span>view V<span class="sy1">&gt;</span>
    requires bidirectional_range<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span>
  <span class="kw1">class</span> reverse_view <span class="sy4">:</span> <span class="kw1">public</span> view_interface<span class="sy1">&lt;</span>reverse_view<span class="sy1">&lt;</span>V<span class="sy1">&gt;&gt;</span> <span class="br0">{</span>
  <span class="kw1">private</span><span class="sy4">:</span>
    V base_ <span class="sy1">=</span> V<span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>  <span class="co1">// exposition only</span>
  <span class="kw1">public</span><span class="sy4">:</span>
    reverse_view<span class="br0">(</span><span class="br0">)</span> requires default_initializable<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> <span class="sy1">=</span> <span class="kw1">default</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> <span class="kw1">explicit</span> reverse_view<span class="br0">(</span>V r<span class="br0">)</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> V base<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span><span class="sy3">&amp;</span> requires copy_constructible<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> <span class="br0">{</span> <span class="kw1">return</span> base_<span class="sy4">;</span> <span class="br0">}</span>
    <span class="kw4">constexpr</span> V base<span class="br0">(</span><span class="br0">)</span> <span class="sy3">&amp;&amp;</span> <span class="br0">{</span> <span class="kw1">return</span> std<span class="sy4">::</span><span class="me2">move</span><span class="br0">(</span>base_<span class="br0">)</span><span class="sy4">;</span> <span class="br0">}</span>
 
    <span class="kw4">constexpr</span> reverse_iterator<span class="sy1">&lt;</span>iterator_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;&gt;</span> begin<span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> reverse_iterator<span class="sy1">&lt;</span>iterator_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;&gt;</span> begin<span class="br0">(</span><span class="br0">)</span> requires common_range<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> <span class="kw4">auto</span> begin<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span> requires common_range<span class="sy1">&lt;</span><span class="kw4">const</span> V<span class="sy1">&gt;</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> reverse_iterator<span class="sy1">&lt;</span>iterator_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;&gt;</span> end<span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> <span class="kw4">auto</span> end<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span> requires common_range<span class="sy1">&lt;</span><span class="kw4">const</span> V<span class="sy1">&gt;</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> <span class="kw4">auto</span> size<span class="br0">(</span><span class="br0">)</span> requires sized_range<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> <span class="br0">{</span>
      <span class="kw1">return</span> <a href="../ranges/size.html"><span class="kw3103">ranges::<span class="me2">size</span></span></a><span class="br0">(</span>base_<span class="br0">)</span><span class="sy4">;</span>
    <span class="br0">}</span>
 
    <span class="kw4">constexpr</span> <span class="kw4">auto</span> size<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span> requires sized_range<span class="sy1">&lt;</span><span class="kw4">const</span> V<span class="sy1">&gt;</span> <span class="br0">{</span>
      <span class="kw1">return</span> <a href="../ranges/size.html"><span class="kw3103">ranges::<span class="me2">size</span></span></a><span class="br0">(</span>base_<span class="br0">)</span><span class="sy4">;</span>
    <span class="br0">}</span>
  <span class="br0">}</span><span class="sy4">;</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> R<span class="sy1">&gt;</span>
    reverse_view<span class="br0">(</span>R<span class="sy3">&amp;&amp;</span><span class="br0">)</span> <span class="sy2">-</span><span class="sy1">&gt;</span> reverse_view<span class="sy1">&lt;</span><a href="../ranges/all_view.html"><span class="kw2919">views::<span class="me2">all_t</span></span></a><span class="sy1">&lt;</span>R<span class="sy1">&gt;&gt;</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<h4><span class="mw-headline" id="Class_template_std::ranges::elements_view">Class template <span class="t-lc">std::ranges::elements_view</span></span></h4>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">namespace</span> std<span class="sy4">::</span><span class="me2">ranges</span> <span class="br0">{</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> T, size_t N<span class="sy1">&gt;</span>
  concept <span class="coMULTI">/*has-tuple-element*/</span> <span class="sy1">=</span>                   <span class="co1">// exposition only</span>
    requires<span class="br0">(</span>T t<span class="br0">)</span> <span class="br0">{</span>
      <span class="kw1">typename</span> tuple_size<span class="sy1">&lt;</span>T<span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">type</span><span class="sy4">;</span>
      requires N <span class="sy1">&lt;</span> tuple_size_v<span class="sy1">&lt;</span>T<span class="sy1">&gt;</span><span class="sy4">;</span>
      <span class="kw1">typename</span> tuple_element_t<span class="sy1">&lt;</span>N, T<span class="sy1">&gt;</span><span class="sy4">;</span>
      <span class="br0">{</span> <a href="../utility/variant/get.html"><span class="kw3220">std::<span class="me2">get</span></span></a><span class="sy1">&lt;</span>N<span class="sy1">&gt;</span><span class="br0">(</span>t<span class="br0">)</span> <span class="br0">}</span> <span class="sy2">-</span><span class="sy1">&gt;</span> convertible_to<span class="sy1">&lt;</span><span class="kw4">const</span> tuple_element_t<span class="sy1">&lt;</span>N, T<span class="sy1">&gt;</span><span class="sy3">&amp;</span><span class="sy1">&gt;</span><span class="sy4">;</span>
    <span class="br0">}</span><span class="sy4">;</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> T, size_t N<span class="sy1">&gt;</span>
  concept <span class="coMULTI">/*returnable-element*/</span> <span class="sy1">=</span>                  <span class="co1">// exposition only</span>
    is_reference_v<span class="sy1">&lt;</span>T<span class="sy1">&gt;</span> <span class="sy3">||</span> move_constructible<span class="sy1">&lt;</span>tuple_element_t<span class="sy1">&lt;</span>N, T<span class="sy1">&gt;&gt;</span><span class="sy4">;</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span>input_range V, size_t N<span class="sy1">&gt;</span>
    requires view<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> <span class="coMULTI">/*has-tuple-element*/</span><span class="sy1">&lt;</span>range_value_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span>, N<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
             <span class="coMULTI">/*has-tuple-element*/</span><span class="sy1">&lt;</span>remove_reference_t<span class="sy1">&lt;</span>range_reference_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;&gt;</span>, N<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
             <span class="coMULTI">/*returnable-element*/</span><span class="sy1">&lt;</span>range_reference_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span>, N<span class="sy1">&gt;</span>
  <span class="kw1">class</span> elements_view <span class="sy4">:</span> <span class="kw1">public</span> view_interface<span class="sy1">&lt;</span>elements_view<span class="sy1">&lt;</span>V, N<span class="sy1">&gt;&gt;</span> <span class="br0">{</span>
  <span class="kw1">public</span><span class="sy4">:</span>
    elements_view<span class="br0">(</span><span class="br0">)</span> requires default_initializable<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> <span class="sy1">=</span> <span class="kw1">default</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> <span class="kw1">explicit</span> elements_view<span class="br0">(</span>V base<span class="br0">)</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> V base<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span><span class="sy3">&amp;</span> requires copy_constructible<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> <span class="br0">{</span> <span class="kw1">return</span> base_<span class="sy4">;</span> <span class="br0">}</span>
    <span class="kw4">constexpr</span> V base<span class="br0">(</span><span class="br0">)</span> <span class="sy3">&amp;&amp;</span> <span class="br0">{</span> <span class="kw1">return</span> std<span class="sy4">::</span><span class="me2">move</span><span class="br0">(</span>base_<span class="br0">)</span><span class="sy4">;</span> <span class="br0">}</span>
 
    <span class="kw4">constexpr</span> <span class="kw4">auto</span> begin<span class="br0">(</span><span class="br0">)</span> requires <span class="br0">(</span><span class="sy3">!</span><span class="coMULTI">/*simple-view*/</span><span class="sy1">&lt;</span>V<span class="sy1">&gt;</span><span class="br0">)</span>
    <span class="br0">{</span> <span class="kw1">return</span> iterator<span class="sy1">&lt;</span><span class="kw2">false</span><span class="sy1">&gt;</span><span class="br0">(</span><a href="../../../http:/en.cppreference.com/w/cpp/ranges-ranges-placeholder/begin"><span class="kw2885">ranges::<span class="me2">begin</span></span></a><span class="br0">(</span>base_<span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span> <span class="br0">}</span>
 
    <span class="kw4">constexpr</span> <span class="kw4">auto</span> begin<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span> requires range<span class="sy1">&lt;</span><span class="kw4">const</span> V<span class="sy1">&gt;</span>
    <span class="br0">{</span> <span class="kw1">return</span> iterator<span class="sy1">&lt;</span><span class="kw2">true</span><span class="sy1">&gt;</span><span class="br0">(</span><a href="../../../http:/en.cppreference.com/w/cpp/ranges-ranges-placeholder/begin"><span class="kw2885">ranges::<span class="me2">begin</span></span></a><span class="br0">(</span>base_<span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span> <span class="br0">}</span>
 
    <span class="kw4">constexpr</span> <span class="kw4">auto</span> end<span class="br0">(</span><span class="br0">)</span> requires <span class="br0">(</span><span class="sy3">!</span><span class="coMULTI">/*simple-view*/</span><span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> <span class="sy3">!</span>common_range<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span><span class="br0">)</span>
    <span class="br0">{</span> <span class="kw1">return</span> sentinel<span class="sy1">&lt;</span><span class="kw2">false</span><span class="sy1">&gt;</span><span class="br0">{</span><a href="../../../http:/en.cppreference.com/w/cpp/ranges-ranges-placeholder/end"><span class="kw2887">ranges::<span class="me2">end</span></span></a><span class="br0">(</span>base_<span class="br0">)</span><span class="br0">}</span><span class="sy4">;</span> <span class="br0">}</span>
 
    <span class="kw4">constexpr</span> <span class="kw4">auto</span> end<span class="br0">(</span><span class="br0">)</span> requires <span class="br0">(</span><span class="sy3">!</span><span class="coMULTI">/*simple-view*/</span><span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> common_range<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span><span class="br0">)</span>
    <span class="br0">{</span> <span class="kw1">return</span> iterator<span class="sy1">&lt;</span><span class="kw2">false</span><span class="sy1">&gt;</span><span class="br0">{</span><a href="../../../http:/en.cppreference.com/w/cpp/ranges-ranges-placeholder/end"><span class="kw2887">ranges::<span class="me2">end</span></span></a><span class="br0">(</span>base_<span class="br0">)</span><span class="br0">}</span><span class="sy4">;</span> <span class="br0">}</span>
 
    <span class="kw4">constexpr</span> <span class="kw4">auto</span> end<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span> requires range<span class="sy1">&lt;</span><span class="kw4">const</span> V<span class="sy1">&gt;</span>
    <span class="br0">{</span> <span class="kw1">return</span> sentinel<span class="sy1">&lt;</span><span class="kw2">true</span><span class="sy1">&gt;</span><span class="br0">{</span><a href="../../../http:/en.cppreference.com/w/cpp/ranges-ranges-placeholder/end"><span class="kw2887">ranges::<span class="me2">end</span></span></a><span class="br0">(</span>base_<span class="br0">)</span><span class="br0">}</span><span class="sy4">;</span> <span class="br0">}</span>
 
    <span class="kw4">constexpr</span> <span class="kw4">auto</span> end<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span> requires common_range<span class="sy1">&lt;</span><span class="kw4">const</span> V<span class="sy1">&gt;</span>
    <span class="br0">{</span> <span class="kw1">return</span> iterator<span class="sy1">&lt;</span><span class="kw2">true</span><span class="sy1">&gt;</span><span class="br0">{</span><a href="../../../http:/en.cppreference.com/w/cpp/ranges-ranges-placeholder/end"><span class="kw2887">ranges::<span class="me2">end</span></span></a><span class="br0">(</span>base_<span class="br0">)</span><span class="br0">}</span><span class="sy4">;</span> <span class="br0">}</span>
 
    <span class="kw4">constexpr</span> <span class="kw4">auto</span> size<span class="br0">(</span><span class="br0">)</span> requires sized_range<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span>
    <span class="br0">{</span> <span class="kw1">return</span> <a href="../ranges/size.html"><span class="kw3103">ranges::<span class="me2">size</span></span></a><span class="br0">(</span>base_<span class="br0">)</span><span class="sy4">;</span> <span class="br0">}</span>
 
    <span class="kw4">constexpr</span> <span class="kw4">auto</span> size<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span> requires sized_range<span class="sy1">&lt;</span><span class="kw4">const</span> V<span class="sy1">&gt;</span>
    <span class="br0">{</span> <span class="kw1">return</span> <a href="../ranges/size.html"><span class="kw3103">ranges::<span class="me2">size</span></span></a><span class="br0">(</span>base_<span class="br0">)</span><span class="sy4">;</span> <span class="br0">}</span>
 
  <span class="kw1">private</span><span class="sy4">:</span>
    <span class="co1">// class template elements_view::iterator</span>
    <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw4">bool</span><span class="sy1">&gt;</span> <span class="kw1">struct</span> iterator<span class="sy4">;</span>                     <span class="co1">// exposition only</span>
 
    <span class="co1">// class template elements_view::sentinel</span>
    <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw4">bool</span><span class="sy1">&gt;</span> <span class="kw1">struct</span> sentinel<span class="sy4">;</span>                     <span class="co1">// exposition only</span>
 
    V base_ <span class="sy1">=</span> V<span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>                                      <span class="co1">// exposition only</span>
  <span class="br0">}</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<h4><span class="mw-headline" id="Class_template_std::ranges::elements_view::iterator">Class template <span class="t-lc">std::ranges::elements_view::iterator</span></span></h4>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">namespace</span> std<span class="sy4">::</span><span class="me2">ranges</span> <span class="br0">{</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span>input_range V, size_t N<span class="sy1">&gt;</span>
    requires view<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> <span class="coMULTI">/*has-tuple-element*/</span><span class="sy1">&lt;</span>range_value_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span>, N<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
             <span class="coMULTI">/*has-tuple-element*/</span><span class="sy1">&lt;</span>remove_reference_t<span class="sy1">&lt;</span>range_reference_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;&gt;</span>, N<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
             <span class="coMULTI">/*returnable-element*/</span><span class="sy1">&lt;</span>range_reference_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span>, N<span class="sy1">&gt;</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw4">bool</span> Const<span class="sy1">&gt;</span>
  <span class="kw1">class</span> elements_view<span class="sy1">&lt;</span>V, N<span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">iterator</span> <span class="br0">{</span>
    <span class="kw1">using</span> Base <span class="sy1">=</span> <span class="coMULTI">/*maybe-const*/</span><span class="sy1">&lt;</span>Const, V<span class="sy1">&gt;</span><span class="sy4">;</span>             <span class="co1">// exposition only</span>
 
    iterator_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span> current_ <span class="sy1">=</span> iterator_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span><span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>     <span class="co1">// exposition only</span>
 
    <span class="kw4">static</span> <span class="kw4">constexpr</span> decltype<span class="br0">(</span><span class="kw4">auto</span><span class="br0">)</span> <span class="coMULTI">/*get-element*/</span><span class="br0">(</span><span class="kw4">const</span> iterator_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span><span class="sy3">&amp;</span> i<span class="br0">)</span><span class="sy4">;</span>
      <span class="co1">// exposition only</span>
 
  <span class="kw1">public</span><span class="sy4">:</span>
    <span class="kw1">using</span> iterator_concept <span class="sy1">=</span> <span class="coMULTI">/* see description */</span><span class="sy4">;</span>
    <span class="kw1">using</span> iterator_category <span class="sy1">=</span> <span class="coMULTI">/* see description */</span><span class="sy4">;</span>                <span class="co1">// not always present</span>
    <span class="kw1">using</span> value_type <span class="sy1">=</span> remove_cvref_t<span class="sy1">&lt;</span>tuple_element_t<span class="sy1">&lt;</span>N, range_value_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;&gt;&gt;</span><span class="sy4">;</span>
    <span class="kw1">using</span> difference_type <span class="sy1">=</span> range_difference_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span><span class="sy4">;</span>
 
    iterator<span class="br0">(</span><span class="br0">)</span> requires default_initializable<span class="sy1">&lt;</span>iterator_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;&gt;</span> <span class="sy1">=</span> <span class="kw1">default</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> <span class="kw1">explicit</span> iterator<span class="br0">(</span>iterator_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span> current<span class="br0">)</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> iterator<span class="br0">(</span>iterator<span class="sy1">&lt;</span><span class="sy3">!</span>Const<span class="sy1">&gt;</span> i<span class="br0">)</span>
      requires Const <span class="sy3">&amp;&amp;</span> convertible_to<span class="sy1">&lt;</span>iterator_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span>, iterator_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;&gt;</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> <span class="kw4">const</span> iterator_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span><span class="sy3">&amp;</span> base<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span> <span class="sy3">&amp;</span> <span class="kw1">noexcept</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> iterator_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span> base<span class="br0">(</span><span class="br0">)</span> <span class="sy3">&amp;&amp;</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> decltype<span class="br0">(</span><span class="kw4">auto</span><span class="br0">)</span> operator<span class="sy2">*</span><span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span>
    <span class="br0">{</span> <span class="kw1">return</span> <span class="coMULTI">/*get-element*/</span><span class="br0">(</span>current_<span class="br0">)</span><span class="sy4">;</span> <span class="br0">}</span>
 
    <span class="kw4">constexpr</span> iterator<span class="sy3">&amp;</span> operator<span class="sy2">++</span><span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> <span class="kw4">void</span> operator<span class="sy2">++</span><span class="br0">(</span><span class="kw4">int</span><span class="br0">)</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> iterator operator<span class="sy2">++</span><span class="br0">(</span><span class="kw4">int</span><span class="br0">)</span> requires forward_range<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> iterator<span class="sy3">&amp;</span> operator<span class="sy2">--</span><span class="br0">(</span><span class="br0">)</span> requires bidirectional_range<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> iterator operator<span class="sy2">--</span><span class="br0">(</span><span class="kw4">int</span><span class="br0">)</span> requires bidirectional_range<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> iterator<span class="sy3">&amp;</span> operator<span class="sy2">+</span><span class="sy1">=</span><span class="br0">(</span>difference_type x<span class="br0">)</span>
      requires random_access_range<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> iterator<span class="sy3">&amp;</span> operator<span class="sy2">-</span><span class="sy1">=</span><span class="br0">(</span>difference_type x<span class="br0">)</span>
      requires random_access_range<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> decltype<span class="br0">(</span><span class="kw4">auto</span><span class="br0">)</span> operator<span class="br0">[</span><span class="br0">]</span><span class="br0">(</span>difference_type n<span class="br0">)</span> <span class="kw4">const</span>
      requires random_access_range<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span>
    <span class="br0">{</span> <span class="kw1">return</span> <span class="coMULTI">/*get-element*/</span><span class="br0">(</span>current_ <span class="sy2">+</span> n<span class="br0">)</span><span class="sy4">;</span> <span class="br0">}</span>
 
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> operator<span class="sy1">==</span><span class="br0">(</span><span class="kw4">const</span> iterator<span class="sy3">&amp;</span> x, <span class="kw4">const</span> iterator<span class="sy3">&amp;</span> y<span class="br0">)</span>
      requires equality_comparable<span class="sy1">&lt;</span>iterator_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;&gt;</span><span class="sy4">;</span>
 
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> operator<span class="sy1">&lt;</span><span class="br0">(</span><span class="kw4">const</span> iterator<span class="sy3">&amp;</span> x, <span class="kw4">const</span> iterator<span class="sy3">&amp;</span> y<span class="br0">)</span>
      requires random_access_range<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span><span class="sy4">;</span>
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> operator<span class="sy1">&gt;</span><span class="br0">(</span><span class="kw4">const</span> iterator<span class="sy3">&amp;</span> x, <span class="kw4">const</span> iterator<span class="sy3">&amp;</span> y<span class="br0">)</span>
      requires random_access_range<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span><span class="sy4">;</span>
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> operator<span class="sy1">&lt;=</span><span class="br0">(</span><span class="kw4">const</span> iterator<span class="sy3">&amp;</span> x, <span class="kw4">const</span> iterator<span class="sy3">&amp;</span> y<span class="br0">)</span>
      requires random_access_range<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span><span class="sy4">;</span>
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> operator<span class="sy1">&gt;=</span><span class="br0">(</span><span class="kw4">const</span> iterator<span class="sy3">&amp;</span> x, <span class="kw4">const</span> iterator<span class="sy3">&amp;</span> y<span class="br0">)</span>
      requires random_access_range<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span><span class="sy4">;</span>
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> <span class="kw4">auto</span> operator<span class="sy1">&lt;=&gt;</span><span class="br0">(</span><span class="kw4">const</span> iterator<span class="sy3">&amp;</span> x, <span class="kw4">const</span> iterator<span class="sy3">&amp;</span> y<span class="br0">)</span>
      requires random_access_range<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> three_way_comparable<span class="sy1">&lt;</span>iterator_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;&gt;</span><span class="sy4">;</span>
 
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> iterator operator<span class="sy2">+</span><span class="br0">(</span><span class="kw4">const</span> iterator<span class="sy3">&amp;</span> x, difference_type y<span class="br0">)</span>
      requires random_access_range<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span><span class="sy4">;</span>
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> iterator operator<span class="sy2">+</span><span class="br0">(</span>difference_type x, <span class="kw4">const</span> iterator<span class="sy3">&amp;</span> y<span class="br0">)</span>
      requires random_access_range<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span><span class="sy4">;</span>
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> iterator operator<span class="sy2">-</span><span class="br0">(</span><span class="kw4">const</span> iterator<span class="sy3">&amp;</span> x, difference_type y<span class="br0">)</span>
      requires random_access_range<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span><span class="sy4">;</span>
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> difference_type operator<span class="sy2">-</span><span class="br0">(</span><span class="kw4">const</span> iterator<span class="sy3">&amp;</span> x, <span class="kw4">const</span> iterator<span class="sy3">&amp;</span> y<span class="br0">)</span>
      requires sized_sentinel_for<span class="sy1">&lt;</span>iterator_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span>, iterator_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;&gt;</span><span class="sy4">;</span>
  <span class="br0">}</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<h4><span class="mw-headline" id="Class_template_std::ranges::elements_view::sentinel">Class template <span class="t-lc">std::ranges::elements_view::sentinel</span></span></h4>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">namespace</span> std<span class="sy4">::</span><span class="me2">ranges</span> <span class="br0">{</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span>input_range V, size_t N<span class="sy1">&gt;</span>
    requires view<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> <span class="coMULTI">/*has-tuple-element*/</span><span class="sy1">&lt;</span>range_value_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span>, N<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
             <span class="coMULTI">/*has-tuple-element*/</span><span class="sy1">&lt;</span>remove_reference_t<span class="sy1">&lt;</span>range_reference_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;&gt;</span>, N<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
             <span class="coMULTI">/*returnable-element*/</span><span class="sy1">&lt;</span>range_reference_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span>, N<span class="sy1">&gt;</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw4">bool</span> Const<span class="sy1">&gt;</span>
  <span class="kw1">class</span> elements_view<span class="sy1">&lt;</span>V, N<span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">sentinel</span> <span class="br0">{</span>
  <span class="kw1">private</span><span class="sy4">:</span>
    <span class="kw1">using</span> Base <span class="sy1">=</span> <span class="coMULTI">/*maybe-const*/</span><span class="sy1">&lt;</span>Const, V<span class="sy1">&gt;</span><span class="sy4">;</span>             <span class="co1">// exposition only</span>
    sentinel_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span> end_ <span class="sy1">=</span> sentinel_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span><span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>         <span class="co1">// exposition only</span>
  <span class="kw1">public</span><span class="sy4">:</span>
    sentinel<span class="br0">(</span><span class="br0">)</span> <span class="sy1">=</span> <span class="kw1">default</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> <span class="kw1">explicit</span> sentinel<span class="br0">(</span>sentinel_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span> end<span class="br0">)</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> sentinel<span class="br0">(</span>sentinel<span class="sy1">&lt;</span><span class="sy3">!</span>Const<span class="sy1">&gt;</span> other<span class="br0">)</span>
      requires Const <span class="sy3">&amp;&amp;</span> convertible_to<span class="sy1">&lt;</span>sentinel_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span>, sentinel_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;&gt;</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> sentinel_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span> base<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span><span class="sy4">;</span>
 
    <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw4">bool</span> OtherConst<span class="sy1">&gt;</span>
      requires sentinel_for<span class="sy1">&lt;</span>sentinel_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span>, iterator_t<span class="sy1">&lt;</span><span class="coMULTI">/*maybe-const*/</span><span class="sy1">&lt;</span>OtherConst, V<span class="sy1">&gt;&gt;&gt;</span>
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> operator<span class="sy1">==</span><span class="br0">(</span><span class="kw4">const</span> iterator<span class="sy1">&lt;</span>OtherConst<span class="sy1">&gt;</span><span class="sy3">&amp;</span> x, <span class="kw4">const</span> sentinel<span class="sy3">&amp;</span> y<span class="br0">)</span><span class="sy4">;</span>
 
    <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw4">bool</span> OtherConst<span class="sy1">&gt;</span>
      requires sized_sentinel_for<span class="sy1">&lt;</span>sentinel_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span>,
        iterator_t<span class="sy1">&lt;</span><span class="coMULTI">/*maybe-const*/</span><span class="sy1">&lt;</span>OtherConst, V<span class="sy1">&gt;&gt;&gt;</span>
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> range_difference_t<span class="sy1">&lt;</span><span class="coMULTI">/*maybe-const*/</span><span class="sy1">&lt;</span>OtherConst, V<span class="sy1">&gt;&gt;</span>
      operator<span class="sy2">-</span><span class="br0">(</span><span class="kw4">const</span> iterator<span class="sy1">&lt;</span>OtherConst<span class="sy1">&gt;</span><span class="sy3">&amp;</span> x, <span class="kw4">const</span> sentinel<span class="sy3">&amp;</span> y<span class="br0">)</span><span class="sy4">;</span>
 
    <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw4">bool</span> OtherConst<span class="sy1">&gt;</span>
      requires sized_sentinel_for<span class="sy1">&lt;</span>sentinel_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span>,
        iterator_t<span class="sy1">&lt;</span><span class="coMULTI">/*maybe-const*/</span><span class="sy1">&lt;</span>OtherConst, V<span class="sy1">&gt;&gt;&gt;</span>
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> range_difference_t<span class="sy1">&lt;</span><span class="coMULTI">/*maybe-const*/</span><span class="sy1">&lt;</span>OtherConst, V<span class="sy1">&gt;&gt;</span>
      operator<span class="sy2">-</span><span class="br0">(</span><span class="kw4">const</span> sentinel<span class="sy3">&amp;</span> x, <span class="kw4">const</span> iterator<span class="sy1">&lt;</span>OtherConst<span class="sy1">&gt;</span><span class="sy3">&amp;</span> y<span class="br0">)</span><span class="sy4">;</span>
  <span class="br0">}</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<h4><span class="mw-headline" id="Class_template_std::ranges::zip_view">Class template <span class="t-lc">std::ranges::zip_view</span></span></h4>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">namespace</span> std<span class="sy4">::</span><span class="me2">ranges</span> <span class="br0">{</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span>... <span class="me1">Rs</span><span class="sy1">&gt;</span>
  concept <span class="coMULTI">/*zip-is-common*/</span> <span class="sy1">=</span>                                <span class="co1">// exposition only</span>
    <span class="br0">(</span>sizeof...<span class="br0">(</span>Rs<span class="br0">)</span> <span class="sy1">==</span> <span class="nu0">1</span> <span class="sy3">&amp;&amp;</span> <span class="br0">(</span>common_range<span class="sy1">&lt;</span>Rs<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> ...<span class="br0">)</span><span class="br0">)</span> <span class="sy3">||</span>
    <span class="br0">(</span><span class="sy3">!</span><span class="br0">(</span>bidirectional_range<span class="sy1">&lt;</span>Rs<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> ...<span class="br0">)</span> <span class="sy3">&amp;&amp;</span> <span class="br0">(</span>common_range<span class="sy1">&lt;</span>Rs<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> ...<span class="br0">)</span><span class="br0">)</span> <span class="sy3">||</span>
    <span class="br0">(</span><span class="br0">(</span>random_access_range<span class="sy1">&lt;</span>Rs<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> ...<span class="br0">)</span> <span class="sy3">&amp;&amp;</span> <span class="br0">(</span>sized_range<span class="sy1">&lt;</span>Rs<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> ...<span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span>... <span class="me1">Ts</span><span class="sy1">&gt;</span>
    <span class="kw1">using</span> <span class="coMULTI">/*tuple-or-pair*/</span> <span class="sy1">=</span> <span class="coMULTI">/* see description */</span><span class="sy4">;</span>         <span class="co1">// exposition only</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> F, <span class="kw1">class</span> Tuple<span class="sy1">&gt;</span>
  <span class="kw4">constexpr</span> <span class="kw4">auto</span> <span class="coMULTI">/*tuple-transform*/</span><span class="br0">(</span>F<span class="sy3">&amp;&amp;</span> f, Tuple<span class="sy3">&amp;&amp;</span> tuple<span class="br0">)</span> <span class="br0">{</span> <span class="co1">// exposition only</span>
    <span class="kw1">return</span> apply<span class="br0">(</span><span class="br0">[</span><span class="sy3">&amp;</span><span class="br0">]</span><span class="sy1">&lt;</span><span class="kw1">class</span>... <span class="me1">Ts</span><span class="sy1">&gt;</span><span class="br0">(</span>Ts<span class="sy3">&amp;&amp;</span>... <span class="me1">elements</span><span class="br0">)</span> <span class="br0">{</span>
      <span class="kw1">return</span> <span class="coMULTI">/*tuple-or-pair*/</span><span class="sy1">&lt;</span>invoke_result_t<span class="sy1">&lt;</span>F<span class="sy3">&amp;</span>, Ts<span class="sy1">&gt;</span>...<span class="sy1">&gt;</span><span class="br0">(</span>
        invoke<span class="br0">(</span>f, <a href="../utility/forward.html"><span class="kw1120">std::<span class="me2">forward</span></span></a><span class="sy1">&lt;</span>Ts<span class="sy1">&gt;</span><span class="br0">(</span>elements<span class="br0">)</span><span class="br0">)</span>...
      <span class="br0">)</span><span class="sy4">;</span>
    <span class="br0">}</span>, <a href="../utility/forward.html"><span class="kw1120">std::<span class="me2">forward</span></span></a><span class="sy1">&lt;</span>Tuple<span class="sy1">&gt;</span><span class="br0">(</span>tuple<span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
  <span class="br0">}</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> F, <span class="kw1">class</span> Tuple<span class="sy1">&gt;</span>
  <span class="kw4">constexpr</span> <span class="kw4">void</span> <span class="coMULTI">/*tuple-for-each*/</span><span class="br0">(</span>F<span class="sy3">&amp;&amp;</span> f, Tuple<span class="sy3">&amp;&amp;</span> tuple<span class="br0">)</span> <span class="br0">{</span> <span class="co1">// exposition only</span>
    apply<span class="br0">(</span><span class="br0">[</span><span class="sy3">&amp;</span><span class="br0">]</span><span class="sy1">&lt;</span><span class="kw1">class</span>... <span class="me1">Ts</span><span class="sy1">&gt;</span><span class="br0">(</span>Ts<span class="sy3">&amp;&amp;</span>... <span class="me1">elements</span><span class="br0">)</span> <span class="br0">{</span>
      <span class="br0">(</span>invoke<span class="br0">(</span>f, <a href="../utility/forward.html"><span class="kw1120">std::<span class="me2">forward</span></span></a><span class="sy1">&lt;</span>Ts<span class="sy1">&gt;</span><span class="br0">(</span>elements<span class="br0">)</span><span class="br0">)</span>, ...<span class="br0">)</span><span class="sy4">;</span>
    <span class="br0">}</span>, <a href="../utility/forward.html"><span class="kw1120">std::<span class="me2">forward</span></span></a><span class="sy1">&lt;</span>Tuple<span class="sy1">&gt;</span><span class="br0">(</span>tuple<span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
  <span class="br0">}</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span>input_range... <span class="me1">Views</span><span class="sy1">&gt;</span>
    requires <span class="br0">(</span>view<span class="sy1">&lt;</span>Views<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> ...<span class="br0">)</span> <span class="sy3">&amp;&amp;</span> <span class="br0">(</span>sizeof...<span class="br0">(</span>Views<span class="br0">)</span> <span class="sy1">&gt;</span> <span class="nu0">0</span><span class="br0">)</span>
  <span class="kw1">class</span> zip_view <span class="sy4">:</span> <span class="kw1">public</span> view_interface<span class="sy1">&lt;</span>zip_view<span class="sy1">&lt;</span>Views...<span class="sy1">&gt;&gt;</span> <span class="br0">{</span>
    tuple<span class="sy1">&lt;</span>Views...<span class="sy1">&gt;</span> views_<span class="sy4">;</span>             <span class="co1">// exposition only</span>
 
    <span class="co1">// class template zip_view::iterator</span>
    <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw4">bool</span><span class="sy1">&gt;</span> <span class="kw1">class</span> iterator<span class="sy4">;</span>      <span class="co1">// exposition only</span>
 
    <span class="co1">// class template zip_view::sentinel</span>
    <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw4">bool</span><span class="sy1">&gt;</span> <span class="kw1">class</span> sentinel<span class="sy4">;</span>      <span class="co1">// exposition only</span>
 
  <span class="kw1">public</span><span class="sy4">:</span>
    zip_view<span class="br0">(</span><span class="br0">)</span> <span class="sy1">=</span> <span class="kw1">default</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> <span class="kw1">explicit</span> zip_view<span class="br0">(</span>Views... <span class="me1">views</span><span class="br0">)</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> <span class="kw4">auto</span> begin<span class="br0">(</span><span class="br0">)</span> requires <span class="br0">(</span><span class="sy3">!</span><span class="br0">(</span><span class="coMULTI">/*simple-view*/</span><span class="sy1">&lt;</span>Views<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> ...<span class="br0">)</span><span class="br0">)</span> <span class="br0">{</span>
      <span class="kw1">return</span> iterator<span class="sy1">&lt;</span><span class="kw2">false</span><span class="sy1">&gt;</span><span class="br0">(</span><span class="coMULTI">/*tuple-transform*/</span><span class="br0">(</span><a href="../../../http:/en.cppreference.com/w/cpp/ranges-ranges-placeholder/begin"><span class="kw2885">ranges::<span class="me2">begin</span></span></a>, views_<span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
    <span class="br0">}</span>
    <span class="kw4">constexpr</span> <span class="kw4">auto</span> begin<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span> requires <span class="br0">(</span>range<span class="sy1">&lt;</span><span class="kw4">const</span> Views<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> ...<span class="br0">)</span> <span class="br0">{</span>
      <span class="kw1">return</span> iterator<span class="sy1">&lt;</span><span class="kw2">true</span><span class="sy1">&gt;</span><span class="br0">(</span><span class="coMULTI">/*tuple-transform*/</span><span class="br0">(</span><a href="../../../http:/en.cppreference.com/w/cpp/ranges-ranges-placeholder/begin"><span class="kw2885">ranges::<span class="me2">begin</span></span></a>, views_<span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
    <span class="br0">}</span>
 
    <span class="kw4">constexpr</span> <span class="kw4">auto</span> end<span class="br0">(</span><span class="br0">)</span> requires <span class="br0">(</span><span class="sy3">!</span><span class="br0">(</span><span class="coMULTI">/*simple-view*/</span><span class="sy1">&lt;</span>Views<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> ...<span class="br0">)</span><span class="br0">)</span> <span class="br0">{</span>
      <span class="kw1">if</span> <span class="kw4">constexpr</span> <span class="br0">(</span><span class="sy3">!</span><span class="coMULTI">/*zip-is-common*/</span><span class="sy1">&lt;</span>Views...<span class="sy1">&gt;</span><span class="br0">)</span> <span class="br0">{</span>
        <span class="kw1">return</span> sentinel<span class="sy1">&lt;</span><span class="kw2">false</span><span class="sy1">&gt;</span><span class="br0">(</span><span class="coMULTI">/*tuple-transform*/</span><span class="br0">(</span><a href="../../../http:/en.cppreference.com/w/cpp/ranges-ranges-placeholder/end"><span class="kw2887">ranges::<span class="me2">end</span></span></a>, views_<span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
      <span class="br0">}</span> <span class="kw1">else</span> <span class="kw1">if</span> <span class="kw4">constexpr</span> <span class="br0">(</span><span class="br0">(</span>random_access_range<span class="sy1">&lt;</span>Views<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> ...<span class="br0">)</span><span class="br0">)</span> <span class="br0">{</span>
        <span class="kw1">return</span> begin<span class="br0">(</span><span class="br0">)</span> <span class="sy2">+</span> iter_difference_t<span class="sy1">&lt;</span>iterator<span class="sy1">&lt;</span><span class="kw2">false</span><span class="sy1">&gt;&gt;</span><span class="br0">(</span>size<span class="br0">(</span><span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
      <span class="br0">}</span> <span class="kw1">else</span> <span class="br0">{</span>
        <span class="kw1">return</span> iterator<span class="sy1">&lt;</span><span class="kw2">false</span><span class="sy1">&gt;</span><span class="br0">(</span><span class="coMULTI">/*tuple-transform*/</span><span class="br0">(</span><a href="../../../http:/en.cppreference.com/w/cpp/ranges-ranges-placeholder/end"><span class="kw2887">ranges::<span class="me2">end</span></span></a>, views_<span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
      <span class="br0">}</span>
    <span class="br0">}</span>
 
    <span class="kw4">constexpr</span> <span class="kw4">auto</span> end<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span> requires <span class="br0">(</span>range<span class="sy1">&lt;</span><span class="kw4">const</span> Views<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> ...<span class="br0">)</span> <span class="br0">{</span>
      <span class="kw1">if</span> <span class="kw4">constexpr</span> <span class="br0">(</span><span class="sy3">!</span><span class="coMULTI">/*zip-is-common*/</span><span class="sy1">&lt;</span><span class="kw4">const</span> Views...<span class="sy1">&gt;</span><span class="br0">)</span> <span class="br0">{</span>
        <span class="kw1">return</span> sentinel<span class="sy1">&lt;</span><span class="kw2">true</span><span class="sy1">&gt;</span><span class="br0">(</span><span class="coMULTI">/*tuple-transform*/</span><span class="br0">(</span><a href="../../../http:/en.cppreference.com/w/cpp/ranges-ranges-placeholder/end"><span class="kw2887">ranges::<span class="me2">end</span></span></a>, views_<span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
      <span class="br0">}</span> <span class="kw1">else</span> <span class="kw1">if</span> <span class="kw4">constexpr</span> <span class="br0">(</span><span class="br0">(</span>random_access_range<span class="sy1">&lt;</span><span class="kw4">const</span> Views<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> ...<span class="br0">)</span><span class="br0">)</span> <span class="br0">{</span>
        <span class="kw1">return</span> begin<span class="br0">(</span><span class="br0">)</span> <span class="sy2">+</span> iter_difference_t<span class="sy1">&lt;</span>iterator<span class="sy1">&lt;</span><span class="kw2">true</span><span class="sy1">&gt;&gt;</span><span class="br0">(</span>size<span class="br0">(</span><span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
      <span class="br0">}</span> <span class="kw1">else</span> <span class="br0">{</span>
        <span class="kw1">return</span> iterator<span class="sy1">&lt;</span><span class="kw2">true</span><span class="sy1">&gt;</span><span class="br0">(</span><span class="coMULTI">/*tuple-transform*/</span><span class="br0">(</span><a href="../../../http:/en.cppreference.com/w/cpp/ranges-ranges-placeholder/end"><span class="kw2887">ranges::<span class="me2">end</span></span></a>, views_<span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
      <span class="br0">}</span>
    <span class="br0">}</span>
 
    <span class="kw4">constexpr</span> <span class="kw4">auto</span> size<span class="br0">(</span><span class="br0">)</span> requires <span class="br0">(</span>sized_range<span class="sy1">&lt;</span>Views<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> ...<span class="br0">)</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> <span class="kw4">auto</span> size<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span> requires <span class="br0">(</span>sized_range<span class="sy1">&lt;</span><span class="kw4">const</span> Views<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> ...<span class="br0">)</span><span class="sy4">;</span>
  <span class="br0">}</span><span class="sy4">;</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span>... <span class="me1">Rs</span><span class="sy1">&gt;</span>
    zip_view<span class="br0">(</span>Rs<span class="sy3">&amp;&amp;</span>...<span class="br0">)</span> <span class="sy2">-</span><span class="sy1">&gt;</span> zip_view<span class="sy1">&lt;</span><a href="../ranges/all_view.html"><span class="kw2919">views::<span class="me2">all_t</span></span></a><span class="sy1">&lt;</span>Rs<span class="sy1">&gt;</span>...<span class="sy1">&gt;</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<h4><span class="mw-headline" id="Class_template_std::ranges::zip_view::iterator">Class template <span class="t-lc">std::ranges::zip_view::iterator</span></span></h4>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">namespace</span> std<span class="sy4">::</span><span class="me2">ranges</span> <span class="br0">{</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw4">bool</span> Const, <span class="kw1">class</span>... <span class="me1">Views</span><span class="sy1">&gt;</span>
    concept <span class="coMULTI">/*all-random-access*/</span> <span class="sy1">=</span>                 <span class="co1">// exposition only</span>
      <span class="br0">(</span>random_access_range<span class="sy1">&lt;</span><span class="coMULTI">/*maybe-const*/</span><span class="sy1">&lt;</span>Const, Views<span class="sy1">&gt;&gt;</span> <span class="sy3">&amp;&amp;</span> ...<span class="br0">)</span><span class="sy4">;</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw4">bool</span> Const, <span class="kw1">class</span>... <span class="me1">Views</span><span class="sy1">&gt;</span>
    concept <span class="coMULTI">/*all-bidirectional*/</span> <span class="sy1">=</span>                 <span class="co1">// exposition only</span>
      <span class="br0">(</span>bidirectional_range<span class="sy1">&lt;</span><span class="coMULTI">/*maybe-const*/</span><span class="sy1">&lt;</span>Const, Views<span class="sy1">&gt;&gt;</span> <span class="sy3">&amp;&amp;</span> ...<span class="br0">)</span><span class="sy4">;</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw4">bool</span> Const, <span class="kw1">class</span>... <span class="me1">Views</span><span class="sy1">&gt;</span>
    concept <span class="coMULTI">/*all-forward*/</span> <span class="sy1">=</span>                       <span class="co1">// exposition only</span>
      <span class="br0">(</span>forward_range<span class="sy1">&lt;</span><span class="coMULTI">/*maybe-const*/</span><span class="sy1">&lt;</span>Const, Views<span class="sy1">&gt;&gt;</span> <span class="sy3">&amp;&amp;</span> ...<span class="br0">)</span><span class="sy4">;</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span>input_range... <span class="me1">Views</span><span class="sy1">&gt;</span>
    requires <span class="br0">(</span>view<span class="sy1">&lt;</span>Views<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> ...<span class="br0">)</span> <span class="sy3">&amp;&amp;</span> <span class="br0">(</span>sizeof...<span class="br0">(</span>Views<span class="br0">)</span> <span class="sy1">&gt;</span> <span class="nu0">0</span><span class="br0">)</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw4">bool</span> Const<span class="sy1">&gt;</span>
  <span class="kw1">class</span> zip_view<span class="sy1">&lt;</span>Views...<span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">iterator</span> <span class="br0">{</span>
    <span class="coMULTI">/*tuple-or-pair*/</span><span class="sy1">&lt;</span>iterator_t<span class="sy1">&lt;</span><span class="coMULTI">/*maybe-const*/</span><span class="sy1">&lt;</span>Const, Views<span class="sy1">&gt;&gt;</span>...<span class="sy1">&gt;</span>
      current_<span class="sy4">;</span>       <span class="co1">// exposition only</span>
    <span class="kw4">constexpr</span> <span class="kw1">explicit</span> iterator<span class="br0">(</span><span class="coMULTI">/*tuple-or-pair*/</span><span class="sy1">&lt;</span>iterator_t<span class="sy1">&lt;</span>
      <span class="coMULTI">/*maybe-const*/</span><span class="sy1">&lt;</span>Const, Views<span class="sy1">&gt;&gt;</span>...<span class="sy1">&gt;</span><span class="br0">)</span><span class="sy4">;</span>          <span class="co1">// exposition only</span>
  <span class="kw1">public</span><span class="sy4">:</span>
    <span class="kw1">using</span> iterator_category <span class="sy1">=</span> input_iterator_tag<span class="sy4">;</span>   <span class="co1">// not always present</span>
    <span class="kw1">using</span> iterator_concept  <span class="sy1">=</span> <span class="coMULTI">/* see description */</span><span class="sy4">;</span>
    <span class="kw1">using</span> value_type <span class="sy1">=</span> <span class="coMULTI">/*tuple-or-pair*/</span><span class="sy1">&lt;</span>range_value_t<span class="sy1">&lt;</span>
      <span class="coMULTI">/*maybe-const*/</span><span class="sy1">&lt;</span>Const, Views<span class="sy1">&gt;&gt;</span>...<span class="sy1">&gt;</span><span class="sy4">;</span>
    <span class="kw1">using</span> difference_type <span class="sy1">=</span> common_type_t<span class="sy1">&lt;</span>range_difference_t<span class="sy1">&lt;</span>
      <span class="coMULTI">/*maybe-const*/</span><span class="sy1">&lt;</span>Const, Views<span class="sy1">&gt;&gt;</span>...<span class="sy1">&gt;</span><span class="sy4">;</span>
 
    iterator<span class="br0">(</span><span class="br0">)</span> <span class="sy1">=</span> <span class="kw1">default</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> iterator<span class="br0">(</span>iterator<span class="sy1">&lt;</span><span class="sy3">!</span>Const<span class="sy1">&gt;</span> i<span class="br0">)</span>
      requires Const <span class="sy3">&amp;&amp;</span> <span class="br0">(</span>convertible_to<span class="sy1">&lt;</span>iterator_t<span class="sy1">&lt;</span>Views<span class="sy1">&gt;</span>,
        iterator_t<span class="sy1">&lt;</span><span class="coMULTI">/*maybe-const*/</span><span class="sy1">&lt;</span>Const, Views<span class="sy1">&gt;&gt;&gt;</span> <span class="sy3">&amp;&amp;</span> ...<span class="br0">)</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> <span class="kw4">auto</span> operator<span class="sy2">*</span><span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> iterator<span class="sy3">&amp;</span> operator<span class="sy2">++</span><span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> <span class="kw4">void</span> operator<span class="sy2">++</span><span class="br0">(</span><span class="kw4">int</span><span class="br0">)</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> iterator operator<span class="sy2">++</span><span class="br0">(</span><span class="kw4">int</span><span class="br0">)</span> requires <span class="coMULTI">/*all-forward*/</span><span class="sy1">&lt;</span>Const, Views...<span class="sy1">&gt;</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> iterator<span class="sy3">&amp;</span> operator<span class="sy2">--</span><span class="br0">(</span><span class="br0">)</span> requires <span class="coMULTI">/*all-bidirectional*/</span><span class="sy1">&lt;</span>Const, Views...<span class="sy1">&gt;</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> iterator operator<span class="sy2">--</span><span class="br0">(</span><span class="kw4">int</span><span class="br0">)</span> requires <span class="coMULTI">/*all-bidirectional*/</span><span class="sy1">&lt;</span>Const, Views...<span class="sy1">&gt;</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> iterator<span class="sy3">&amp;</span> operator<span class="sy2">+</span><span class="sy1">=</span><span class="br0">(</span>difference_type x<span class="br0">)</span>
      requires <span class="coMULTI">/*all-random-access*/</span><span class="sy1">&lt;</span>Const, Views...<span class="sy1">&gt;</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> iterator<span class="sy3">&amp;</span> operator<span class="sy2">-</span><span class="sy1">=</span><span class="br0">(</span>difference_type x<span class="br0">)</span>
      requires <span class="coMULTI">/*all-random-access*/</span><span class="sy1">&lt;</span>Const, Views...<span class="sy1">&gt;</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> <span class="kw4">auto</span> operator<span class="br0">[</span><span class="br0">]</span><span class="br0">(</span>difference_type n<span class="br0">)</span> <span class="kw4">const</span>
      requires <span class="coMULTI">/*all-random-access*/</span><span class="sy1">&lt;</span>Const, Views...<span class="sy1">&gt;</span><span class="sy4">;</span>
 
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> operator<span class="sy1">==</span><span class="br0">(</span><span class="kw4">const</span> iterator<span class="sy3">&amp;</span> x, <span class="kw4">const</span> iterator<span class="sy3">&amp;</span> y<span class="br0">)</span>
      requires <span class="br0">(</span>equality_comparable<span class="sy1">&lt;</span>iterator_t<span class="sy1">&lt;</span><span class="coMULTI">/*maybe-const*/</span><span class="sy1">&lt;</span>Const, Views<span class="sy1">&gt;&gt;&gt;</span> <span class="sy3">&amp;&amp;</span> ...<span class="br0">)</span><span class="sy4">;</span>
 
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> operator<span class="sy1">&lt;</span><span class="br0">(</span><span class="kw4">const</span> iterator<span class="sy3">&amp;</span> x, <span class="kw4">const</span> iterator<span class="sy3">&amp;</span> y<span class="br0">)</span>
      requires <span class="coMULTI">/*all-random-access*/</span><span class="sy1">&lt;</span>Const, Views...<span class="sy1">&gt;</span><span class="sy4">;</span>
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> operator<span class="sy1">&gt;</span><span class="br0">(</span><span class="kw4">const</span> iterator<span class="sy3">&amp;</span> x, <span class="kw4">const</span> iterator<span class="sy3">&amp;</span> y<span class="br0">)</span>
      requires <span class="coMULTI">/*all-random-access*/</span><span class="sy1">&lt;</span>Const, Views...<span class="sy1">&gt;</span><span class="sy4">;</span>
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> operator<span class="sy1">&lt;=</span><span class="br0">(</span><span class="kw4">const</span> iterator<span class="sy3">&amp;</span> x, <span class="kw4">const</span> iterator<span class="sy3">&amp;</span> y<span class="br0">)</span>
      requires <span class="coMULTI">/*all-random-access*/</span><span class="sy1">&lt;</span>Const, Views...<span class="sy1">&gt;</span><span class="sy4">;</span>
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> operator<span class="sy1">&gt;=</span><span class="br0">(</span><span class="kw4">const</span> iterator<span class="sy3">&amp;</span> x, <span class="kw4">const</span> iterator<span class="sy3">&amp;</span> y<span class="br0">)</span>
      requires <span class="coMULTI">/*all-random-access*/</span><span class="sy1">&lt;</span>Const, Views...<span class="sy1">&gt;</span><span class="sy4">;</span>
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> <span class="kw4">auto</span> operator<span class="sy1">&lt;=&gt;</span><span class="br0">(</span><span class="kw4">const</span> iterator<span class="sy3">&amp;</span> x, <span class="kw4">const</span> iterator<span class="sy3">&amp;</span> y<span class="br0">)</span>
      requires <span class="coMULTI">/*all-random-access*/</span><span class="sy1">&lt;</span>Const, Views...<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
               <span class="br0">(</span>three_way_comparable<span class="sy1">&lt;</span>iterator_t<span class="sy1">&lt;</span><span class="coMULTI">/*maybe-const*/</span><span class="sy1">&lt;</span>Const, Views<span class="sy1">&gt;&gt;&gt;</span> <span class="sy3">&amp;&amp;</span> ...<span class="br0">)</span><span class="sy4">;</span>
 
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> iterator operator<span class="sy2">+</span><span class="br0">(</span><span class="kw4">const</span> iterator<span class="sy3">&amp;</span> i, difference_type n<span class="br0">)</span>
      requires <span class="coMULTI">/*all-random-access*/</span><span class="sy1">&lt;</span>Const, Views...<span class="sy1">&gt;</span><span class="sy4">;</span>
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> iterator operator<span class="sy2">+</span><span class="br0">(</span>difference_type n, <span class="kw4">const</span> iterator<span class="sy3">&amp;</span> i<span class="br0">)</span>
      requires <span class="coMULTI">/*all-random-access*/</span><span class="sy1">&lt;</span>Const, Views...<span class="sy1">&gt;</span><span class="sy4">;</span>
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> iterator operator<span class="sy2">-</span><span class="br0">(</span><span class="kw4">const</span> iterator<span class="sy3">&amp;</span> i, difference_type n<span class="br0">)</span>
      requires <span class="coMULTI">/*all-random-access*/</span><span class="sy1">&lt;</span>Const, Views...<span class="sy1">&gt;</span><span class="sy4">;</span>
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> difference_type operator<span class="sy2">-</span><span class="br0">(</span><span class="kw4">const</span> iterator<span class="sy3">&amp;</span> x, <span class="kw4">const</span> iterator<span class="sy3">&amp;</span> y<span class="br0">)</span>
      requires <span class="br0">(</span>sized_sentinel_for<span class="sy1">&lt;</span>iterator_t<span class="sy1">&lt;</span><span class="coMULTI">/*maybe-const*/</span><span class="sy1">&lt;</span>Const, Views<span class="sy1">&gt;&gt;</span>,
                                   iterator_t<span class="sy1">&lt;</span><span class="coMULTI">/*maybe-const*/</span><span class="sy1">&lt;</span>Const, Views<span class="sy1">&gt;&gt;&gt;</span> <span class="sy3">&amp;&amp;</span> ...<span class="br0">)</span><span class="sy4">;</span>
 
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> <span class="kw4">auto</span> iter_move<span class="br0">(</span><span class="kw4">const</span> iterator<span class="sy3">&amp;</span> i<span class="br0">)</span> <span class="kw1">noexcept</span><span class="br0">(</span><span class="coMULTI">/* see description */</span><span class="br0">)</span><span class="sy4">;</span>
 
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> <span class="kw4">void</span> iter_swap<span class="br0">(</span><span class="kw4">const</span> iterator<span class="sy3">&amp;</span> l, <span class="kw4">const</span> iterator<span class="sy3">&amp;</span> r<span class="br0">)</span>
      <span class="kw1">noexcept</span><span class="br0">(</span><span class="coMULTI">/* see description */</span><span class="br0">)</span>
      requires <span class="br0">(</span>indirectly_swappable<span class="sy1">&lt;</span>iterator_t<span class="sy1">&lt;</span><span class="coMULTI">/*maybe-const*/</span><span class="sy1">&lt;</span>Const, Views<span class="sy1">&gt;&gt;&gt;</span> <span class="sy3">&amp;&amp;</span> ...<span class="br0">)</span><span class="sy4">;</span>
  <span class="br0">}</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<h4><span class="mw-headline" id="Class_template_std::ranges::zip_view::sentinel">Class template <span class="t-lc">std::ranges::zip_view::sentinel</span></span></h4>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">namespace</span> std<span class="sy4">::</span><span class="me2">ranges</span> <span class="br0">{</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span>input_range... <span class="me1">Views</span><span class="sy1">&gt;</span>
    requires <span class="br0">(</span>view<span class="sy1">&lt;</span>Views<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> ...<span class="br0">)</span> <span class="sy3">&amp;&amp;</span> <span class="br0">(</span>sizeof...<span class="br0">(</span>Views<span class="br0">)</span> <span class="sy1">&gt;</span> <span class="nu0">0</span><span class="br0">)</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw4">bool</span> Const<span class="sy1">&gt;</span>
  <span class="kw1">class</span> zip_view<span class="sy1">&lt;</span>Views...<span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">sentinel</span> <span class="br0">{</span>
    <span class="coMULTI">/*tuple-or-pair*/</span><span class="sy1">&lt;</span>sentinel_t<span class="sy1">&lt;</span><span class="coMULTI">/*maybe-const*/</span><span class="sy1">&lt;</span>Const, Views<span class="sy1">&gt;&gt;</span>...<span class="sy1">&gt;</span>
      end_<span class="sy4">;</span>   <span class="co1">// exposition only</span>
    <span class="kw4">constexpr</span> <span class="kw1">explicit</span> sentinel<span class="br0">(</span><span class="coMULTI">/*tuple-or-pair*/</span><span class="sy1">&lt;</span>sentinel_t<span class="sy1">&lt;</span>
      <span class="coMULTI">/*maybe-const*/</span><span class="sy1">&lt;</span>Const, Views<span class="sy1">&gt;&gt;</span>...<span class="sy1">&gt;</span> end<span class="br0">)</span><span class="sy4">;</span>  <span class="co1">// exposition only</span>
  <span class="kw1">public</span><span class="sy4">:</span>
    sentinel<span class="br0">(</span><span class="br0">)</span> <span class="sy1">=</span> <span class="kw1">default</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> sentinel<span class="br0">(</span>sentinel<span class="sy1">&lt;</span><span class="sy3">!</span>Const<span class="sy1">&gt;</span> i<span class="br0">)</span>
      requires Const <span class="sy3">&amp;&amp;</span>
               <span class="br0">(</span>convertible_to<span class="sy1">&lt;</span>sentinel_t<span class="sy1">&lt;</span>Views<span class="sy1">&gt;</span>, sentinel_t<span class="sy1">&lt;</span>
                 <span class="coMULTI">/*maybe-const*/</span><span class="sy1">&lt;</span>Const, Views<span class="sy1">&gt;&gt;&gt;</span> <span class="sy3">&amp;&amp;</span> ...<span class="br0">)</span><span class="sy4">;</span>
 
    <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw4">bool</span> OtherConst<span class="sy1">&gt;</span>
      requires <span class="br0">(</span>sentinel_for<span class="sy1">&lt;</span>sentinel_t<span class="sy1">&lt;</span><span class="coMULTI">/*maybe-const*/</span><span class="sy1">&lt;</span>Const, Views<span class="sy1">&gt;&gt;</span>,
                             iterator_t<span class="sy1">&lt;</span><span class="coMULTI">/*maybe-const*/</span><span class="sy1">&lt;</span>OtherConst, Views<span class="sy1">&gt;&gt;&gt;</span> <span class="sy3">&amp;&amp;</span> ...<span class="br0">)</span>
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> operator<span class="sy1">==</span><span class="br0">(</span><span class="kw4">const</span> iterator<span class="sy1">&lt;</span>OtherConst<span class="sy1">&gt;</span><span class="sy3">&amp;</span> x, <span class="kw4">const</span> sentinel<span class="sy3">&amp;</span> y<span class="br0">)</span><span class="sy4">;</span>
 
    <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw4">bool</span> OtherConst<span class="sy1">&gt;</span>
      requires <span class="br0">(</span>sized_sentinel_for<span class="sy1">&lt;</span>sentinel_t<span class="sy1">&lt;</span><span class="coMULTI">/*maybe-const*/</span><span class="sy1">&lt;</span>Const, Views<span class="sy1">&gt;&gt;</span>,
                                   iterator_t<span class="sy1">&lt;</span><span class="coMULTI">/*maybe-const*/</span><span class="sy1">&lt;</span>OtherConst, Views<span class="sy1">&gt;&gt;&gt;</span> <span class="sy3">&amp;&amp;</span> ...<span class="br0">)</span>
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> common_type_t<span class="sy1">&lt;</span>range_difference_t<span class="sy1">&lt;</span>
      <span class="coMULTI">/*maybe-const*/</span><span class="sy1">&lt;</span>OtherConst, Views<span class="sy1">&gt;&gt;</span>...<span class="sy1">&gt;</span>
      operator<span class="sy2">-</span><span class="br0">(</span><span class="kw4">const</span> iterator<span class="sy1">&lt;</span>OtherConst<span class="sy1">&gt;</span><span class="sy3">&amp;</span> x, <span class="kw4">const</span> sentinel<span class="sy3">&amp;</span> y<span class="br0">)</span><span class="sy4">;</span>
 
    <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw4">bool</span> OtherConst<span class="sy1">&gt;</span>
      requires <span class="br0">(</span>sized_sentinel_for<span class="sy1">&lt;</span>sentinel_t<span class="sy1">&lt;</span><span class="coMULTI">/*maybe-const*/</span><span class="sy1">&lt;</span>Const, Views<span class="sy1">&gt;&gt;</span>,
                                   iterator_t<span class="sy1">&lt;</span><span class="coMULTI">/*maybe-const*/</span><span class="sy1">&lt;</span>OtherConst, Views<span class="sy1">&gt;&gt;&gt;</span> <span class="sy3">&amp;&amp;</span> ...<span class="br0">)</span>
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> common_type_t<span class="sy1">&lt;</span>range_difference_t<span class="sy1">&lt;</span>
      <span class="coMULTI">/*maybe-const*/</span><span class="sy1">&lt;</span>OtherConst, Views<span class="sy1">&gt;&gt;</span>...<span class="sy1">&gt;</span>
      operator<span class="sy2">-</span><span class="br0">(</span><span class="kw4">const</span> sentinel<span class="sy3">&amp;</span> y, <span class="kw4">const</span> iterator<span class="sy1">&lt;</span>OtherConst<span class="sy1">&gt;</span><span class="sy3">&amp;</span> x<span class="br0">)</span><span class="sy4">;</span>
  <span class="br0">}</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<h4><span class="mw-headline" id="Class_template_std::ranges::zip_transform_view">Class template <span class="t-lc">std::ranges::zip_transform_view</span></span></h4>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">namespace</span> std<span class="sy4">::</span><span class="me2">ranges</span> <span class="br0">{</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span>copy_constructible F, input_range... <span class="me1">Views</span><span class="sy1">&gt;</span>
    requires <span class="br0">(</span>view<span class="sy1">&lt;</span>Views<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> ...<span class="br0">)</span> <span class="sy3">&amp;&amp;</span> <span class="br0">(</span>sizeof...<span class="br0">(</span>Views<span class="br0">)</span> <span class="sy1">&gt;</span> <span class="nu0">0</span><span class="br0">)</span> <span class="sy3">&amp;&amp;</span> is_object_v<span class="sy1">&lt;</span>F<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
              regular_invocable<span class="sy1">&lt;</span>F<span class="sy3">&amp;</span>, range_reference_t<span class="sy1">&lt;</span>Views<span class="sy1">&gt;</span>...<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
              <span class="coMULTI">/*can-reference*/</span><span class="sy1">&lt;</span>invoke_result_t<span class="sy1">&lt;</span>F<span class="sy3">&amp;</span>, range_reference_t<span class="sy1">&lt;</span>Views<span class="sy1">&gt;</span>...<span class="sy1">&gt;&gt;</span>
  <span class="kw1">class</span> zip_transform_view <span class="sy4">:</span> <span class="kw1">public</span> view_interface<span class="sy1">&lt;</span>zip_transform_view<span class="sy1">&lt;</span>F, Views...<span class="sy1">&gt;&gt;</span> <span class="br0">{</span>
    <span class="coMULTI">/*copyable-box*/</span><span class="sy1">&lt;</span>F<span class="sy1">&gt;</span> fun_<span class="sy4">;</span>               <span class="co1">// exposition only</span>
    zip_view<span class="sy1">&lt;</span>Views...<span class="sy1">&gt;</span> zip_<span class="sy4">;</span>                <span class="co1">// exposition only</span>
 
    <span class="kw1">using</span> InnerView <span class="sy1">=</span> zip_view<span class="sy1">&lt;</span>Views...<span class="sy1">&gt;</span><span class="sy4">;</span>   <span class="co1">// exposition only</span>
    <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw4">bool</span> Const<span class="sy1">&gt;</span>
      <span class="kw1">using</span> ziperator <span class="sy1">=</span> iterator_t<span class="sy1">&lt;</span><span class="coMULTI">/*maybe-const*/</span><span class="sy1">&lt;</span>Const, InnerView<span class="sy1">&gt;&gt;</span><span class="sy4">;</span> <span class="co1">// exposition only</span>
    <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw4">bool</span> Const<span class="sy1">&gt;</span>
      <span class="kw1">using</span> zentinel <span class="sy1">=</span> sentinel_t<span class="sy1">&lt;</span><span class="coMULTI">/*maybe-const*/</span><span class="sy1">&lt;</span>Const, InnerView<span class="sy1">&gt;&gt;</span><span class="sy4">;</span>  <span class="co1">// exposition only</span>
 
    <span class="co1">// class template zip_transform_view::iterator</span>
    <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw4">bool</span><span class="sy1">&gt;</span> <span class="kw1">class</span> iterator<span class="sy4">;</span>          <span class="co1">// exposition only</span>
 
    <span class="co1">// class template zip_transform_view::sentinel</span>
    <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw4">bool</span><span class="sy1">&gt;</span> <span class="kw1">class</span> sentinel<span class="sy4">;</span>          <span class="co1">// exposition only</span>
 
  <span class="kw1">public</span><span class="sy4">:</span>
    zip_transform_view<span class="br0">(</span><span class="br0">)</span> <span class="sy1">=</span> <span class="kw1">default</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> <span class="kw1">explicit</span> zip_transform_view<span class="br0">(</span>F fun, Views... <span class="me1">views</span><span class="br0">)</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> <span class="kw4">auto</span> begin<span class="br0">(</span><span class="br0">)</span> <span class="br0">{</span> <span class="kw1">return</span> iterator<span class="sy1">&lt;</span><span class="kw2">false</span><span class="sy1">&gt;</span><span class="br0">(</span><span class="sy2">*</span>this, zip_.<span class="me1">begin</span><span class="br0">(</span><span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span> <span class="br0">}</span>
 
    <span class="kw4">constexpr</span> <span class="kw4">auto</span> begin<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span>
      requires range<span class="sy1">&lt;</span><span class="kw4">const</span> InnerView<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
               regular_invocable<span class="sy1">&lt;</span><span class="kw4">const</span> F<span class="sy3">&amp;</span>, range_reference_t<span class="sy1">&lt;</span><span class="kw4">const</span> Views<span class="sy1">&gt;</span>...<span class="sy1">&gt;</span> <span class="br0">{</span>
      <span class="kw1">return</span> iterator<span class="sy1">&lt;</span><span class="kw2">true</span><span class="sy1">&gt;</span><span class="br0">(</span><span class="sy2">*</span>this, zip_.<span class="me1">begin</span><span class="br0">(</span><span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
    <span class="br0">}</span>
 
    <span class="kw4">constexpr</span> <span class="kw4">auto</span> end<span class="br0">(</span><span class="br0">)</span> <span class="br0">{</span>
      <span class="kw1">if</span> <span class="kw4">constexpr</span> <span class="br0">(</span>common_range<span class="sy1">&lt;</span>InnerView<span class="sy1">&gt;</span><span class="br0">)</span> <span class="br0">{</span>
        <span class="kw1">return</span> iterator<span class="sy1">&lt;</span><span class="kw2">false</span><span class="sy1">&gt;</span><span class="br0">(</span><span class="sy2">*</span>this, zip_.<span class="me1">end</span><span class="br0">(</span><span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
      <span class="br0">}</span> <span class="kw1">else</span> <span class="br0">{</span>
        <span class="kw1">return</span> sentinel<span class="sy1">&lt;</span><span class="kw2">false</span><span class="sy1">&gt;</span><span class="br0">(</span>zip_.<span class="me1">end</span><span class="br0">(</span><span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
      <span class="br0">}</span>
    <span class="br0">}</span>
 
    <span class="kw4">constexpr</span> <span class="kw4">auto</span> end<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span>
      requires range<span class="sy1">&lt;</span><span class="kw4">const</span> InnerView<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
               regular_invocable<span class="sy1">&lt;</span><span class="kw4">const</span> F<span class="sy3">&amp;</span>, range_reference_t<span class="sy1">&lt;</span><span class="kw4">const</span> Views<span class="sy1">&gt;</span>...<span class="sy1">&gt;</span> <span class="br0">{</span>
      <span class="kw1">if</span> <span class="kw4">constexpr</span> <span class="br0">(</span>common_range<span class="sy1">&lt;</span><span class="kw4">const</span> InnerView<span class="sy1">&gt;</span><span class="br0">)</span> <span class="br0">{</span>
        <span class="kw1">return</span> iterator<span class="sy1">&lt;</span><span class="kw2">true</span><span class="sy1">&gt;</span><span class="br0">(</span><span class="sy2">*</span>this, zip_.<span class="me1">end</span><span class="br0">(</span><span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
      <span class="br0">}</span> <span class="kw1">else</span> <span class="br0">{</span>
        <span class="kw1">return</span> sentinel<span class="sy1">&lt;</span><span class="kw2">true</span><span class="sy1">&gt;</span><span class="br0">(</span>zip_.<span class="me1">end</span><span class="br0">(</span><span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
      <span class="br0">}</span>
    <span class="br0">}</span>
 
    <span class="kw4">constexpr</span> <span class="kw4">auto</span> size<span class="br0">(</span><span class="br0">)</span> requires sized_range<span class="sy1">&lt;</span>InnerView<span class="sy1">&gt;</span> <span class="br0">{</span>
      <span class="kw1">return</span> zip_.<span class="me1">size</span><span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>
    <span class="br0">}</span>
 
    <span class="kw4">constexpr</span> <span class="kw4">auto</span> size<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span> requires sized_range<span class="sy1">&lt;</span><span class="kw4">const</span> InnerView<span class="sy1">&gt;</span> <span class="br0">{</span>
      <span class="kw1">return</span> zip_.<span class="me1">size</span><span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>
    <span class="br0">}</span>
  <span class="br0">}</span><span class="sy4">;</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> F, <span class="kw1">class</span>... <span class="me1">Rs</span><span class="sy1">&gt;</span>
    zip_transform_view<span class="br0">(</span>F, Rs<span class="sy3">&amp;&amp;</span>...<span class="br0">)</span> <span class="sy2">-</span><span class="sy1">&gt;</span> zip_transform_view<span class="sy1">&lt;</span>F, <a href="../ranges/all_view.html"><span class="kw2919">views::<span class="me2">all_t</span></span></a><span class="sy1">&lt;</span>Rs<span class="sy1">&gt;</span>...<span class="sy1">&gt;</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<h4><span class="mw-headline" id="Class_template_std::ranges::zip_transform_view::iterator">Class template <span class="t-lc">std::ranges::zip_transform_view::iterator</span></span></h4>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">namespace</span> std<span class="sy4">::</span><span class="me2">ranges</span> <span class="br0">{</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span>copy_constructible F, input_range... <span class="me1">Views</span><span class="sy1">&gt;</span>
    requires <span class="br0">(</span>view<span class="sy1">&lt;</span>Views<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> ...<span class="br0">)</span> <span class="sy3">&amp;&amp;</span> <span class="br0">(</span>sizeof...<span class="br0">(</span>Views<span class="br0">)</span> <span class="sy1">&gt;</span> <span class="nu0">0</span><span class="br0">)</span> <span class="sy3">&amp;&amp;</span> is_object_v<span class="sy1">&lt;</span>F<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
              regular_invocable<span class="sy1">&lt;</span>F<span class="sy3">&amp;</span>, range_reference_t<span class="sy1">&lt;</span>Views<span class="sy1">&gt;</span>...<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
              <span class="coMULTI">/*can-reference*/</span><span class="sy1">&lt;</span>invoke_result_t<span class="sy1">&lt;</span>F<span class="sy3">&amp;</span>, range_reference_t<span class="sy1">&lt;</span>Views<span class="sy1">&gt;</span>...<span class="sy1">&gt;&gt;</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw4">bool</span> Const<span class="sy1">&gt;</span>
  <span class="kw1">class</span> zip_transform_view<span class="sy1">&lt;</span>F, Views...<span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">iterator</span> <span class="br0">{</span>
    <span class="kw1">using</span> Parent <span class="sy1">=</span> <span class="coMULTI">/*maybe-const*/</span><span class="sy1">&lt;</span>Const, zip_transform_view<span class="sy1">&gt;</span><span class="sy4">;</span>  <span class="co1">// exposition only</span>
    <span class="kw1">using</span> Base <span class="sy1">=</span> <span class="coMULTI">/*maybe-const*/</span><span class="sy1">&lt;</span>Const, InnerView<span class="sy1">&gt;</span><span class="sy4">;</span>             <span class="co1">// exposition only</span>
    Parent<span class="sy2">*</span> parent_ <span class="sy1">=</span> nullptr<span class="sy4">;</span>                                  <span class="co1">// exposition only</span>
    ziperator<span class="sy1">&lt;</span>Const<span class="sy1">&gt;</span> inner_<span class="sy4">;</span>                                    <span class="co1">// exposition only</span>
 
    <span class="kw4">constexpr</span> iterator<span class="br0">(</span>Parent<span class="sy3">&amp;</span> parent, ziperator<span class="sy1">&lt;</span>Const<span class="sy1">&gt;</span> inner<span class="br0">)</span><span class="sy4">;</span> <span class="co1">// exposition only</span>
 
  <span class="kw1">public</span><span class="sy4">:</span>
    <span class="kw1">using</span> iterator_category <span class="sy1">=</span> <span class="coMULTI">/* see description */</span><span class="sy4">;</span>            <span class="co1">// not always present</span>
    <span class="kw1">using</span> iterator_concept  <span class="sy1">=</span> <span class="kw1">typename</span> ziperator<span class="sy1">&lt;</span>Const<span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">iterator_concept</span><span class="sy4">;</span>
    <span class="kw1">using</span> value_type <span class="sy1">=</span>
      remove_cvref_t<span class="sy1">&lt;</span>invoke_result_t<span class="sy1">&lt;</span><span class="coMULTI">/*maybe-const*/</span><span class="sy1">&lt;</span>Const, F<span class="sy1">&gt;</span><span class="sy3">&amp;</span>,
                                     range_reference_t<span class="sy1">&lt;</span>
                                       <span class="coMULTI">/*maybe-const*/</span><span class="sy1">&lt;</span>Const, Views<span class="sy1">&gt;&gt;</span>...<span class="sy1">&gt;&gt;</span><span class="sy4">;</span>
    <span class="kw1">using</span> difference_type <span class="sy1">=</span> range_difference_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span><span class="sy4">;</span>
 
    iterator<span class="br0">(</span><span class="br0">)</span> <span class="sy1">=</span> <span class="kw1">default</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> iterator<span class="br0">(</span>iterator<span class="sy1">&lt;</span><span class="sy3">!</span>Const<span class="sy1">&gt;</span> i<span class="br0">)</span>
      requires Const <span class="sy3">&amp;&amp;</span> convertible_to<span class="sy1">&lt;</span>ziperator<span class="sy1">&lt;</span><span class="kw2">false</span><span class="sy1">&gt;</span>, ziperator<span class="sy1">&lt;</span>Const<span class="sy1">&gt;&gt;</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> decltype<span class="br0">(</span><span class="kw4">auto</span><span class="br0">)</span> operator<span class="sy2">*</span><span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span> <span class="kw1">noexcept</span><span class="br0">(</span><span class="coMULTI">/* see description */</span><span class="br0">)</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> iterator<span class="sy3">&amp;</span> operator<span class="sy2">++</span><span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> <span class="kw4">void</span> operator<span class="sy2">++</span><span class="br0">(</span><span class="kw4">int</span><span class="br0">)</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> iterator operator<span class="sy2">++</span><span class="br0">(</span><span class="kw4">int</span><span class="br0">)</span> requires forward_range<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> iterator<span class="sy3">&amp;</span> operator<span class="sy2">--</span><span class="br0">(</span><span class="br0">)</span> requires bidirectional_range<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> iterator operator<span class="sy2">--</span><span class="br0">(</span><span class="kw4">int</span><span class="br0">)</span> requires bidirectional_range<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> iterator<span class="sy3">&amp;</span> operator<span class="sy2">+</span><span class="sy1">=</span><span class="br0">(</span>difference_type x<span class="br0">)</span> requires random_access_range<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> iterator<span class="sy3">&amp;</span> operator<span class="sy2">-</span><span class="sy1">=</span><span class="br0">(</span>difference_type x<span class="br0">)</span> requires random_access_range<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> decltype<span class="br0">(</span><span class="kw4">auto</span><span class="br0">)</span> operator<span class="br0">[</span><span class="br0">]</span><span class="br0">(</span>difference_type n<span class="br0">)</span> <span class="kw4">const</span>
      requires random_access_range<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span><span class="sy4">;</span>
 
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> operator<span class="sy1">==</span><span class="br0">(</span><span class="kw4">const</span> iterator<span class="sy3">&amp;</span> x, <span class="kw4">const</span> iterator<span class="sy3">&amp;</span> y<span class="br0">)</span>
      requires equality_comparable<span class="sy1">&lt;</span>ziperator<span class="sy1">&lt;</span>Const<span class="sy1">&gt;&gt;</span><span class="sy4">;</span>
 
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> operator<span class="sy1">&lt;</span><span class="br0">(</span><span class="kw4">const</span> iterator<span class="sy3">&amp;</span> x, <span class="kw4">const</span> iterator<span class="sy3">&amp;</span> y<span class="br0">)</span>
      requires random_access_range<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span><span class="sy4">;</span>
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> operator<span class="sy1">&gt;</span><span class="br0">(</span><span class="kw4">const</span> iterator<span class="sy3">&amp;</span> x, <span class="kw4">const</span> iterator<span class="sy3">&amp;</span> y<span class="br0">)</span>
      requires random_access_range<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span><span class="sy4">;</span>
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> operator<span class="sy1">&lt;=</span><span class="br0">(</span><span class="kw4">const</span> iterator<span class="sy3">&amp;</span> x, <span class="kw4">const</span> iterator<span class="sy3">&amp;</span> y<span class="br0">)</span>
      requires random_access_range<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span><span class="sy4">;</span>
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> operator<span class="sy1">&gt;=</span><span class="br0">(</span><span class="kw4">const</span> iterator<span class="sy3">&amp;</span> x, <span class="kw4">const</span> iterator<span class="sy3">&amp;</span> y<span class="br0">)</span>
      requires random_access_range<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span><span class="sy4">;</span>
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> <span class="kw4">auto</span> operator<span class="sy1">&lt;=&gt;</span><span class="br0">(</span><span class="kw4">const</span> iterator<span class="sy3">&amp;</span> x, <span class="kw4">const</span> iterator<span class="sy3">&amp;</span> y<span class="br0">)</span>
      requires random_access_range<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> three_way_comparable<span class="sy1">&lt;</span>ziperator<span class="sy1">&lt;</span>Const<span class="sy1">&gt;&gt;</span><span class="sy4">;</span>
 
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> iterator operator<span class="sy2">+</span><span class="br0">(</span><span class="kw4">const</span> iterator<span class="sy3">&amp;</span> i, difference_type n<span class="br0">)</span>
      requires random_access_range<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span><span class="sy4">;</span>
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> iterator operator<span class="sy2">+</span><span class="br0">(</span>difference_type n, <span class="kw4">const</span> iterator<span class="sy3">&amp;</span> i<span class="br0">)</span>
      requires random_access_range<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span><span class="sy4">;</span>
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> iterator operator<span class="sy2">-</span><span class="br0">(</span><span class="kw4">const</span> iterator<span class="sy3">&amp;</span> i, difference_type n<span class="br0">)</span>
      requires random_access_range<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span><span class="sy4">;</span>
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> difference_type operator<span class="sy2">-</span><span class="br0">(</span><span class="kw4">const</span> iterator<span class="sy3">&amp;</span> x, <span class="kw4">const</span> iterator<span class="sy3">&amp;</span> y<span class="br0">)</span>
      requires sized_sentinel_for<span class="sy1">&lt;</span>ziperator<span class="sy1">&lt;</span>Const<span class="sy1">&gt;</span>, ziperator<span class="sy1">&lt;</span>Const<span class="sy1">&gt;&gt;</span><span class="sy4">;</span>
  <span class="br0">}</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<h4><span class="mw-headline" id="Class_template_std::ranges::zip_transform_view::sentinel">Class template <span class="t-lc">std::ranges::zip_transform_view::sentinel</span></span></h4>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">namespace</span> std<span class="sy4">::</span><span class="me2">ranges</span> <span class="br0">{</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span>copy_constructible F, input_range... <span class="me1">Views</span><span class="sy1">&gt;</span>
    requires <span class="br0">(</span>view<span class="sy1">&lt;</span>Views<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> ...<span class="br0">)</span> <span class="sy3">&amp;&amp;</span> <span class="br0">(</span>sizeof...<span class="br0">(</span>Views<span class="br0">)</span> <span class="sy1">&gt;</span> <span class="nu0">0</span><span class="br0">)</span> <span class="sy3">&amp;&amp;</span> is_object_v<span class="sy1">&lt;</span>F<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
              regular_invocable<span class="sy1">&lt;</span>F<span class="sy3">&amp;</span>, range_reference_t<span class="sy1">&lt;</span>Views<span class="sy1">&gt;</span>...<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
              <span class="coMULTI">/*can-reference*/</span><span class="sy1">&lt;</span>invoke_result_t<span class="sy1">&lt;</span>F<span class="sy3">&amp;</span>, range_reference_t<span class="sy1">&lt;</span>Views<span class="sy1">&gt;</span>...<span class="sy1">&gt;&gt;</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw4">bool</span> Const<span class="sy1">&gt;</span>
  <span class="kw1">class</span> zip_transform_view<span class="sy1">&lt;</span>F, Views...<span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">sentinel</span> <span class="br0">{</span>
    zentinel<span class="sy1">&lt;</span>Const<span class="sy1">&gt;</span> inner_<span class="sy4">;</span>                                     <span class="co1">// exposition only</span>
    <span class="kw4">constexpr</span> <span class="kw1">explicit</span> sentinel<span class="br0">(</span>zentinel<span class="sy1">&lt;</span>Const<span class="sy1">&gt;</span> inner<span class="br0">)</span><span class="sy4">;</span>         <span class="co1">// exposition only</span>
 
  <span class="kw1">public</span><span class="sy4">:</span>
    sentinel<span class="br0">(</span><span class="br0">)</span> <span class="sy1">=</span> <span class="kw1">default</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> sentinel<span class="br0">(</span>sentinel<span class="sy1">&lt;</span><span class="sy3">!</span>Const<span class="sy1">&gt;</span> i<span class="br0">)</span>
      requires Const <span class="sy3">&amp;&amp;</span> convertible_to<span class="sy1">&lt;</span>zentinel<span class="sy1">&lt;</span><span class="kw2">false</span><span class="sy1">&gt;</span>, zentinel<span class="sy1">&lt;</span>Const<span class="sy1">&gt;&gt;</span><span class="sy4">;</span>
 
    <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw4">bool</span> OtherConst<span class="sy1">&gt;</span>
      requires sentinel_for<span class="sy1">&lt;</span>zentinel<span class="sy1">&lt;</span>Const<span class="sy1">&gt;</span>, ziperator<span class="sy1">&lt;</span>OtherConst<span class="sy1">&gt;&gt;</span>
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> operator<span class="sy1">==</span><span class="br0">(</span><span class="kw4">const</span> iterator<span class="sy1">&lt;</span>OtherConst<span class="sy1">&gt;</span><span class="sy3">&amp;</span> x, <span class="kw4">const</span> sentinel<span class="sy3">&amp;</span> y<span class="br0">)</span><span class="sy4">;</span>
 
    <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw4">bool</span> OtherConst<span class="sy1">&gt;</span>
      requires sized_sentinel_for<span class="sy1">&lt;</span>zentinel<span class="sy1">&lt;</span>Const<span class="sy1">&gt;</span>, ziperator<span class="sy1">&lt;</span>OtherConst<span class="sy1">&gt;&gt;</span>
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> range_difference_t<span class="sy1">&lt;</span><span class="coMULTI">/*maybe-const*/</span><span class="sy1">&lt;</span>OtherConst, InnerView<span class="sy1">&gt;&gt;</span>
      operator<span class="sy2">-</span><span class="br0">(</span><span class="kw4">const</span> iterator<span class="sy1">&lt;</span>OtherConst<span class="sy1">&gt;</span><span class="sy3">&amp;</span> x, <span class="kw4">const</span> sentinel<span class="sy3">&amp;</span> y<span class="br0">)</span><span class="sy4">;</span>
 
    <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw4">bool</span> OtherConst<span class="sy1">&gt;</span>
      requires sized_sentinel_for<span class="sy1">&lt;</span>zentinel<span class="sy1">&lt;</span>Const<span class="sy1">&gt;</span>, ziperator<span class="sy1">&lt;</span>OtherConst<span class="sy1">&gt;&gt;</span>
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> range_difference_t<span class="sy1">&lt;</span><span class="coMULTI">/*maybe-const*/</span><span class="sy1">&lt;</span>OtherConst, InnerView<span class="sy1">&gt;&gt;</span>
      operator<span class="sy2">-</span><span class="br0">(</span><span class="kw4">const</span> sentinel<span class="sy3">&amp;</span> x, <span class="kw4">const</span> iterator<span class="sy1">&lt;</span>OtherConst<span class="sy1">&gt;</span><span class="sy3">&amp;</span> y<span class="br0">)</span><span class="sy4">;</span>
  <span class="br0">}</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<h4><span class="mw-headline" id="Class_template_std::ranges::adjacent_view">Class template <span class="t-lc">std::ranges::adjacent_view</span></span></h4>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">namespace</span> std<span class="sy4">::</span><span class="me2">ranges</span> <span class="br0">{</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span>forward_range V, size_t N<span class="sy1">&gt;</span>
    requires view<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> <span class="br0">(</span>N <span class="sy1">&gt;</span> <span class="nu0">0</span><span class="br0">)</span>
  <span class="kw1">class</span> adjacent_view <span class="sy4">:</span> <span class="kw1">public</span> view_interface<span class="sy1">&lt;</span>adjacent_view<span class="sy1">&lt;</span>V, N<span class="sy1">&gt;&gt;</span> <span class="br0">{</span>
    V base_ <span class="sy1">=</span> V<span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>                      <span class="co1">// exposition only</span>
 
    <span class="co1">// class template adjacent_view::iterator</span>
    <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw4">bool</span><span class="sy1">&gt;</span> <span class="kw1">class</span> iterator<span class="sy4">;</span>      <span class="co1">// exposition only</span>
 
    <span class="co1">// class template adjacent_view::sentinel</span>
    <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw4">bool</span><span class="sy1">&gt;</span> <span class="kw1">class</span> sentinel<span class="sy4">;</span>      <span class="co1">// exposition only</span>
 
    <span class="kw1">struct</span> <span class="coMULTI">/*as-sentinel*/</span><span class="br0">{</span><span class="br0">}</span><span class="sy4">;</span>               <span class="co1">// exposition only</span>
 
  <span class="kw1">public</span><span class="sy4">:</span>
    adjacent_view<span class="br0">(</span><span class="br0">)</span> requires default_initializable<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> <span class="sy1">=</span> <span class="kw1">default</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> <span class="kw1">explicit</span> adjacent_view<span class="br0">(</span>V base<span class="br0">)</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> <span class="kw4">auto</span> begin<span class="br0">(</span><span class="br0">)</span> requires <span class="br0">(</span><span class="sy3">!</span><span class="coMULTI">/*simple-view*/</span><span class="sy1">&lt;</span>V<span class="sy1">&gt;</span><span class="br0">)</span> <span class="br0">{</span>
      <span class="kw1">return</span> iterator<span class="sy1">&lt;</span><span class="kw2">false</span><span class="sy1">&gt;</span><span class="br0">(</span><a href="../../../http:/en.cppreference.com/w/cpp/ranges-ranges-placeholder/begin"><span class="kw2885">ranges::<span class="me2">begin</span></span></a><span class="br0">(</span>base_<span class="br0">)</span>, <a href="../../../http:/en.cppreference.com/w/cpp/ranges-ranges-placeholder/end"><span class="kw2887">ranges::<span class="me2">end</span></span></a><span class="br0">(</span>base_<span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
    <span class="br0">}</span>
 
    <span class="kw4">constexpr</span> <span class="kw4">auto</span> begin<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span> requires range<span class="sy1">&lt;</span><span class="kw4">const</span> V<span class="sy1">&gt;</span> <span class="br0">{</span>
      <span class="kw1">return</span> iterator<span class="sy1">&lt;</span><span class="kw2">true</span><span class="sy1">&gt;</span><span class="br0">(</span><a href="../../../http:/en.cppreference.com/w/cpp/ranges-ranges-placeholder/begin"><span class="kw2885">ranges::<span class="me2">begin</span></span></a><span class="br0">(</span>base_<span class="br0">)</span>, <a href="../../../http:/en.cppreference.com/w/cpp/ranges-ranges-placeholder/end"><span class="kw2887">ranges::<span class="me2">end</span></span></a><span class="br0">(</span>base_<span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
    <span class="br0">}</span>
 
    <span class="kw4">constexpr</span> <span class="kw4">auto</span> end<span class="br0">(</span><span class="br0">)</span> requires <span class="br0">(</span><span class="sy3">!</span><span class="coMULTI">/*simple-view*/</span><span class="sy1">&lt;</span>V<span class="sy1">&gt;</span><span class="br0">)</span> <span class="br0">{</span>
      <span class="kw1">if</span> <span class="kw4">constexpr</span> <span class="br0">(</span>common_range<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span><span class="br0">)</span> <span class="br0">{</span>
        <span class="kw1">return</span> iterator<span class="sy1">&lt;</span><span class="kw2">false</span><span class="sy1">&gt;</span><span class="br0">(</span><span class="coMULTI">/*as-sentinel*/</span><span class="br0">{</span><span class="br0">}</span>, <a href="../../../http:/en.cppreference.com/w/cpp/ranges-ranges-placeholder/begin"><span class="kw2885">ranges::<span class="me2">begin</span></span></a><span class="br0">(</span>base_<span class="br0">)</span>,
          <a href="../../../http:/en.cppreference.com/w/cpp/ranges-ranges-placeholder/end"><span class="kw2887">ranges::<span class="me2">end</span></span></a><span class="br0">(</span>base_<span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
      <span class="br0">}</span> <span class="kw1">else</span> <span class="br0">{</span>
        <span class="kw1">return</span> sentinel<span class="sy1">&lt;</span><span class="kw2">false</span><span class="sy1">&gt;</span><span class="br0">(</span><a href="../../../http:/en.cppreference.com/w/cpp/ranges-ranges-placeholder/end"><span class="kw2887">ranges::<span class="me2">end</span></span></a><span class="br0">(</span>base_<span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
      <span class="br0">}</span>
    <span class="br0">}</span>
 
    <span class="kw4">constexpr</span> <span class="kw4">auto</span> end<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span> requires range<span class="sy1">&lt;</span><span class="kw4">const</span> V<span class="sy1">&gt;</span> <span class="br0">{</span>
      <span class="kw1">if</span> <span class="kw4">constexpr</span> <span class="br0">(</span>common_range<span class="sy1">&lt;</span><span class="kw4">const</span> V<span class="sy1">&gt;</span><span class="br0">)</span> <span class="br0">{</span>
        <span class="kw1">return</span> iterator<span class="sy1">&lt;</span><span class="kw2">true</span><span class="sy1">&gt;</span><span class="br0">(</span><span class="coMULTI">/*as-sentinel*/</span><span class="br0">{</span><span class="br0">}</span>, <a href="../../../http:/en.cppreference.com/w/cpp/ranges-ranges-placeholder/begin"><span class="kw2885">ranges::<span class="me2">begin</span></span></a><span class="br0">(</span>base_<span class="br0">)</span>,
          <a href="../../../http:/en.cppreference.com/w/cpp/ranges-ranges-placeholder/end"><span class="kw2887">ranges::<span class="me2">end</span></span></a><span class="br0">(</span>base_<span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
      <span class="br0">}</span> <span class="kw1">else</span> <span class="br0">{</span>
        <span class="kw1">return</span> sentinel<span class="sy1">&lt;</span><span class="kw2">true</span><span class="sy1">&gt;</span><span class="br0">(</span><a href="../../../http:/en.cppreference.com/w/cpp/ranges-ranges-placeholder/end"><span class="kw2887">ranges::<span class="me2">end</span></span></a><span class="br0">(</span>base_<span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
      <span class="br0">}</span>
    <span class="br0">}</span>
 
    <span class="kw4">constexpr</span> <span class="kw4">auto</span> size<span class="br0">(</span><span class="br0">)</span> requires sized_range<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> <span class="kw4">auto</span> size<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span> requires sized_range<span class="sy1">&lt;</span><span class="kw4">const</span> V<span class="sy1">&gt;</span><span class="sy4">;</span>
  <span class="br0">}</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<h4><span class="mw-headline" id="Class_template_std::ranges::adjacent_view::iterator">Class template <span class="t-lc">std::ranges::adjacent_view::iterator</span></span></h4>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">namespace</span> std<span class="sy4">::</span><span class="me2">ranges</span> <span class="br0">{</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span>forward_range V, size_t N<span class="sy1">&gt;</span>
    requires view<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> <span class="br0">(</span>N <span class="sy1">&gt;</span> <span class="nu0">0</span><span class="br0">)</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw4">bool</span> Const<span class="sy1">&gt;</span>
  <span class="kw1">class</span> adjacent_view<span class="sy1">&lt;</span>V, N<span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">iterator</span> <span class="br0">{</span>
    <span class="kw1">using</span> Base <span class="sy1">=</span> <span class="coMULTI">/*maybe-const*/</span><span class="sy1">&lt;</span>Const, V<span class="sy1">&gt;</span><span class="sy4">;</span>                             <span class="co1">// exposition only</span>
    array<span class="sy1">&lt;</span>iterator_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span>, N<span class="sy1">&gt;</span> current_ <span class="sy1">=</span> array<span class="sy1">&lt;</span>iterator_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span>, N<span class="sy1">&gt;</span><span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span> <span class="co1">// exposition only</span>
    <span class="kw4">constexpr</span> iterator<span class="br0">(</span>iterator_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span> first, sentinel_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span> last<span class="br0">)</span><span class="sy4">;</span>  <span class="co1">// exposition only</span>
    <span class="kw4">constexpr</span> iterator<span class="br0">(</span><span class="coMULTI">/*as-sentinel*/</span>, iterator_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span> first, iterator_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span> last<span class="br0">)</span><span class="sy4">;</span>
                                                                        <span class="co1">// exposition only</span>
  <span class="kw1">public</span><span class="sy4">:</span>
    <span class="kw1">using</span> iterator_category <span class="sy1">=</span> input_iterator_tag<span class="sy4">;</span>
    <span class="kw1">using</span> iterator_concept  <span class="sy1">=</span> <span class="coMULTI">/* see description */</span><span class="sy4">;</span>
    <span class="kw1">using</span> value_type <span class="sy1">=</span> <span class="coMULTI">/*tuple-or-pair*/</span><span class="sy1">&lt;</span><span class="coMULTI">/*REPEAT*/</span><span class="br0">(</span>range_value_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span>, N<span class="br0">)</span>...<span class="sy1">&gt;</span><span class="sy4">;</span>
    <span class="kw1">using</span> difference_type <span class="sy1">=</span> range_difference_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span><span class="sy4">;</span>
 
    iterator<span class="br0">(</span><span class="br0">)</span> <span class="sy1">=</span> <span class="kw1">default</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> iterator<span class="br0">(</span>iterator<span class="sy1">&lt;</span><span class="sy3">!</span>Const<span class="sy1">&gt;</span> i<span class="br0">)</span>
      requires Const <span class="sy3">&amp;&amp;</span> convertible_to<span class="sy1">&lt;</span>iterator_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span>, iterator_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;&gt;</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> <span class="kw4">auto</span> operator<span class="sy2">*</span><span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> iterator<span class="sy3">&amp;</span> operator<span class="sy2">++</span><span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> iterator operator<span class="sy2">++</span><span class="br0">(</span><span class="kw4">int</span><span class="br0">)</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> iterator<span class="sy3">&amp;</span> operator<span class="sy2">--</span><span class="br0">(</span><span class="br0">)</span> requires bidirectional_range<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> iterator operator<span class="sy2">--</span><span class="br0">(</span><span class="kw4">int</span><span class="br0">)</span> requires bidirectional_range<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> iterator<span class="sy3">&amp;</span> operator<span class="sy2">+</span><span class="sy1">=</span><span class="br0">(</span>difference_type x<span class="br0">)</span>
      requires random_access_range<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> iterator<span class="sy3">&amp;</span> operator<span class="sy2">-</span><span class="sy1">=</span><span class="br0">(</span>difference_type x<span class="br0">)</span>
      requires random_access_range<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> <span class="kw4">auto</span> operator<span class="br0">[</span><span class="br0">]</span><span class="br0">(</span>difference_type n<span class="br0">)</span> <span class="kw4">const</span>
      requires random_access_range<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span><span class="sy4">;</span>
 
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> operator<span class="sy1">==</span><span class="br0">(</span><span class="kw4">const</span> iterator<span class="sy3">&amp;</span> x, <span class="kw4">const</span> iterator<span class="sy3">&amp;</span> y<span class="br0">)</span><span class="sy4">;</span>
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> operator<span class="sy1">&lt;</span><span class="br0">(</span><span class="kw4">const</span> iterator<span class="sy3">&amp;</span> x, <span class="kw4">const</span> iterator<span class="sy3">&amp;</span> y<span class="br0">)</span>
      requires random_access_range<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span><span class="sy4">;</span>
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> operator<span class="sy1">&gt;</span><span class="br0">(</span><span class="kw4">const</span> iterator<span class="sy3">&amp;</span> x, <span class="kw4">const</span> iterator<span class="sy3">&amp;</span> y<span class="br0">)</span>
      requires random_access_range<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span><span class="sy4">;</span>
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> operator<span class="sy1">&lt;=</span><span class="br0">(</span><span class="kw4">const</span> iterator<span class="sy3">&amp;</span> x, <span class="kw4">const</span> iterator<span class="sy3">&amp;</span> y<span class="br0">)</span>
      requires random_access_range<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span><span class="sy4">;</span>
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> operator<span class="sy1">&gt;=</span><span class="br0">(</span><span class="kw4">const</span> iterator<span class="sy3">&amp;</span> x, <span class="kw4">const</span> iterator<span class="sy3">&amp;</span> y<span class="br0">)</span>
      requires random_access_range<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span><span class="sy4">;</span>
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> <span class="kw4">auto</span> operator<span class="sy1">&lt;=&gt;</span><span class="br0">(</span><span class="kw4">const</span> iterator<span class="sy3">&amp;</span> x, <span class="kw4">const</span> iterator<span class="sy3">&amp;</span> y<span class="br0">)</span>
      requires random_access_range<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
               three_way_comparable<span class="sy1">&lt;</span>iterator_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;&gt;</span><span class="sy4">;</span>
 
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> iterator operator<span class="sy2">+</span><span class="br0">(</span><span class="kw4">const</span> iterator<span class="sy3">&amp;</span> i, difference_type n<span class="br0">)</span>
      requires random_access_range<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span><span class="sy4">;</span>
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> iterator operator<span class="sy2">+</span><span class="br0">(</span>difference_type n, <span class="kw4">const</span> iterator<span class="sy3">&amp;</span> i<span class="br0">)</span>
      requires random_access_range<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span><span class="sy4">;</span>
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> iterator operator<span class="sy2">-</span><span class="br0">(</span><span class="kw4">const</span> iterator<span class="sy3">&amp;</span> i, difference_type n<span class="br0">)</span>
      requires random_access_range<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span><span class="sy4">;</span>
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> difference_type operator<span class="sy2">-</span><span class="br0">(</span><span class="kw4">const</span> iterator<span class="sy3">&amp;</span> x, <span class="kw4">const</span> iterator<span class="sy3">&amp;</span> y<span class="br0">)</span>
      requires sized_sentinel_for<span class="sy1">&lt;</span>iterator_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span>, iterator_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;&gt;</span><span class="sy4">;</span>
 
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> <span class="kw4">auto</span> iter_move<span class="br0">(</span><span class="kw4">const</span> iterator<span class="sy3">&amp;</span> i<span class="br0">)</span> <span class="kw1">noexcept</span><span class="br0">(</span><span class="coMULTI">/* see description */</span><span class="br0">)</span><span class="sy4">;</span>
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> <span class="kw4">void</span> iter_swap<span class="br0">(</span><span class="kw4">const</span> iterator<span class="sy3">&amp;</span> l, <span class="kw4">const</span> iterator<span class="sy3">&amp;</span> r<span class="br0">)</span>
      <span class="kw1">noexcept</span><span class="br0">(</span><span class="coMULTI">/* see description */</span><span class="br0">)</span>
      requires indirectly_swappable<span class="sy1">&lt;</span>iterator_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;&gt;</span><span class="sy4">;</span>
  <span class="br0">}</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<h4><span class="mw-headline" id="Class_template_std::ranges::adjacent_view::sentinel">Class template <span class="t-lc">std::ranges::adjacent_view::sentinel</span></span></h4>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">namespace</span> std<span class="sy4">::</span><span class="me2">ranges</span> <span class="br0">{</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span>forward_range V, size_t N<span class="sy1">&gt;</span>
    requires view<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> <span class="br0">(</span>N <span class="sy1">&gt;</span> <span class="nu0">0</span><span class="br0">)</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw4">bool</span> Const<span class="sy1">&gt;</span>
  <span class="kw1">class</span> adjacent_view<span class="sy1">&lt;</span>V, N<span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">sentinel</span> <span class="br0">{</span>
    <span class="kw1">using</span> Base <span class="sy1">=</span> <span class="coMULTI">/*maybe-const*/</span><span class="sy1">&lt;</span>Const, V<span class="sy1">&gt;</span><span class="sy4">;</span>                     <span class="co1">// exposition only</span>
    sentinel_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span> end_ <span class="sy1">=</span> sentinel_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span><span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>                 <span class="co1">// exposition only</span>
    <span class="kw4">constexpr</span> <span class="kw1">explicit</span> sentinel<span class="br0">(</span>sentinel_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span> end<span class="br0">)</span><span class="sy4">;</span>          <span class="co1">// exposition only</span>
 
  <span class="kw1">public</span><span class="sy4">:</span>
    sentinel<span class="br0">(</span><span class="br0">)</span> <span class="sy1">=</span> <span class="kw1">default</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> sentinel<span class="br0">(</span>sentinel<span class="sy1">&lt;</span><span class="sy3">!</span>Const<span class="sy1">&gt;</span> i<span class="br0">)</span>
      requires Const <span class="sy3">&amp;&amp;</span> convertible_to<span class="sy1">&lt;</span>sentinel_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span>, sentinel_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;&gt;</span><span class="sy4">;</span>
 
    <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw4">bool</span> OtherConst<span class="sy1">&gt;</span>
      requires sentinel_for<span class="sy1">&lt;</span>sentinel_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span>, iterator_t<span class="sy1">&lt;</span><span class="coMULTI">/*maybe-const*/</span><span class="sy1">&lt;</span>OtherConst, V<span class="sy1">&gt;&gt;&gt;</span>
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> operator<span class="sy1">==</span><span class="br0">(</span><span class="kw4">const</span> iterator<span class="sy1">&lt;</span>OtherConst<span class="sy1">&gt;</span><span class="sy3">&amp;</span> x, <span class="kw4">const</span> sentinel<span class="sy3">&amp;</span> y<span class="br0">)</span><span class="sy4">;</span>
 
    <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw4">bool</span> OtherConst<span class="sy1">&gt;</span>
      requires sized_sentinel_for<span class="sy1">&lt;</span>sentinel_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span>, iterator_t<span class="sy1">&lt;</span>
        <span class="coMULTI">/*maybe-const*/</span><span class="sy1">&lt;</span>OtherConst, V<span class="sy1">&gt;&gt;&gt;</span>
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> range_difference_t<span class="sy1">&lt;</span><span class="coMULTI">/*maybe-const*/</span><span class="sy1">&lt;</span>OtherConst, V<span class="sy1">&gt;&gt;</span>
      operator<span class="sy2">-</span><span class="br0">(</span><span class="kw4">const</span> iterator<span class="sy1">&lt;</span>OtherConst<span class="sy1">&gt;</span><span class="sy3">&amp;</span> x, <span class="kw4">const</span> sentinel<span class="sy3">&amp;</span> y<span class="br0">)</span><span class="sy4">;</span>
 
    <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw4">bool</span> OtherConst<span class="sy1">&gt;</span>
      requires sized_sentinel_for<span class="sy1">&lt;</span>sentinel_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span>, iterator_t<span class="sy1">&lt;</span>
        <span class="coMULTI">/*maybe-const*/</span><span class="sy1">&lt;</span>OtherConst, V<span class="sy1">&gt;&gt;&gt;</span>
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> range_difference_t<span class="sy1">&lt;</span><span class="coMULTI">/*maybe-const*/</span><span class="sy1">&lt;</span>OtherConst, V<span class="sy1">&gt;&gt;</span>
      operator<span class="sy2">-</span><span class="br0">(</span><span class="kw4">const</span> sentinel<span class="sy3">&amp;</span> y, <span class="kw4">const</span> iterator<span class="sy1">&lt;</span>OtherConst<span class="sy1">&gt;</span><span class="sy3">&amp;</span> x<span class="br0">)</span><span class="sy4">;</span>
  <span class="br0">}</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<h4><span class="mw-headline" id="Class_template_std::ranges::adjacent_transform_view">Class template <span class="t-lc">std::ranges::adjacent_transform_view</span></span></h4>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">namespace</span> std<span class="sy4">::</span><span class="me2">ranges</span> <span class="br0">{</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span>forward_range V, copy_constructible F, size_t N<span class="sy1">&gt;</span>
   requires view<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> <span class="br0">(</span>N <span class="sy1">&gt;</span> <span class="nu0">0</span><span class="br0">)</span> <span class="sy3">&amp;&amp;</span> is_object_v<span class="sy1">&lt;</span>F<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
            regular_invocable<span class="sy1">&lt;</span>F<span class="sy3">&amp;</span>, <span class="coMULTI">/*REPEAT*/</span><span class="br0">(</span>range_reference_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span>, N<span class="br0">)</span>...<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
            <span class="coMULTI">/*can-reference*/</span><span class="sy1">&lt;</span>invoke_result_t<span class="sy1">&lt;</span>F<span class="sy3">&amp;</span>, <span class="coMULTI">/*REPEAT*/</span><span class="br0">(</span>range_reference_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span>, N<span class="br0">)</span>...<span class="sy1">&gt;&gt;</span>
  <span class="kw1">class</span> adjacent_transform_view <span class="sy4">:</span>
    <span class="kw1">public</span> view_interface<span class="sy1">&lt;</span>adjacent_transform_view<span class="sy1">&lt;</span>V, F, N<span class="sy1">&gt;&gt;</span> <span class="br0">{</span>
    <span class="coMULTI">/*copyable-box*/</span><span class="sy1">&lt;</span>F<span class="sy1">&gt;</span> fun_<span class="sy4">;</span>                       <span class="co1">// exposition only</span>
    adjacent_view<span class="sy1">&lt;</span>V, N<span class="sy1">&gt;</span> inner_<span class="sy4">;</span>                 <span class="co1">// exposition only</span>
 
    <span class="kw1">using</span> InnerView <span class="sy1">=</span> adjacent_view<span class="sy1">&lt;</span>V, N<span class="sy1">&gt;</span><span class="sy4">;</span>      <span class="co1">// exposition only</span>
    <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw4">bool</span> Const<span class="sy1">&gt;</span>
      <span class="kw1">using</span> <span class="coMULTI">/*inner-iterator*/</span> <span class="sy1">=</span>
        iterator_t<span class="sy1">&lt;</span><span class="coMULTI">/*maybe-const*/</span><span class="sy1">&lt;</span>Const, InnerView<span class="sy1">&gt;&gt;</span><span class="sy4">;</span>         <span class="co1">// exposition only</span>
    <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw4">bool</span> Const<span class="sy1">&gt;</span>
      <span class="kw1">using</span> <span class="coMULTI">/*inner-sentinel*/</span> <span class="sy1">=</span>
        sentinel_t<span class="sy1">&lt;</span><span class="coMULTI">/*maybe-const*/</span><span class="sy1">&lt;</span>Const, InnerView<span class="sy1">&gt;&gt;</span><span class="sy4">;</span>         <span class="co1">// exposition only</span>
 
    <span class="co1">// class template adjacent_transform_view::iterator</span>
    <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw4">bool</span><span class="sy1">&gt;</span> <span class="kw1">class</span> iterator<span class="sy4">;</span>              <span class="co1">// exposition only</span>
 
    <span class="co1">// class template adjacent_transform_view::sentinel</span>
    <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw4">bool</span><span class="sy1">&gt;</span> <span class="kw1">class</span> sentinel<span class="sy4">;</span>              <span class="co1">// exposition only</span>
 
  <span class="kw1">public</span><span class="sy4">:</span>
    adjacent_transform_view<span class="br0">(</span><span class="br0">)</span> <span class="sy1">=</span> <span class="kw1">default</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> <span class="kw1">explicit</span> adjacent_transform_view<span class="br0">(</span>V base, F fun<span class="br0">)</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> <span class="kw4">auto</span> begin<span class="br0">(</span><span class="br0">)</span> <span class="br0">{</span>
      <span class="kw1">return</span> iterator<span class="sy1">&lt;</span><span class="kw2">false</span><span class="sy1">&gt;</span><span class="br0">(</span><span class="sy2">*</span>this, inner_.<span class="me1">begin</span><span class="br0">(</span><span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
    <span class="br0">}</span>
 
    <span class="kw4">constexpr</span> <span class="kw4">auto</span> begin<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span>
      requires range<span class="sy1">&lt;</span><span class="kw4">const</span> InnerView<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
               regular_invocable<span class="sy1">&lt;</span><span class="kw4">const</span> F<span class="sy3">&amp;</span>, <span class="coMULTI">/*REPEAT*/</span><span class="br0">(</span>range_reference_t<span class="sy1">&lt;</span><span class="kw4">const</span> V<span class="sy1">&gt;</span>, N<span class="br0">)</span>...<span class="sy1">&gt;</span> <span class="br0">{</span>
      <span class="kw1">return</span> iterator<span class="sy1">&lt;</span><span class="kw2">true</span><span class="sy1">&gt;</span><span class="br0">(</span><span class="sy2">*</span>this, inner_.<span class="me1">begin</span><span class="br0">(</span><span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
    <span class="br0">}</span>
 
    <span class="kw4">constexpr</span> <span class="kw4">auto</span> end<span class="br0">(</span><span class="br0">)</span> <span class="br0">{</span>
      <span class="kw1">if</span> <span class="kw4">constexpr</span> <span class="br0">(</span>common_range<span class="sy1">&lt;</span>InnerView<span class="sy1">&gt;</span><span class="br0">)</span> <span class="br0">{</span>
        <span class="kw1">return</span> iterator<span class="sy1">&lt;</span><span class="kw2">false</span><span class="sy1">&gt;</span><span class="br0">(</span><span class="sy2">*</span>this, inner_.<span class="me1">end</span><span class="br0">(</span><span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
      <span class="br0">}</span> <span class="kw1">else</span> <span class="br0">{</span>
        <span class="kw1">return</span> sentinel<span class="sy1">&lt;</span><span class="kw2">false</span><span class="sy1">&gt;</span><span class="br0">(</span>inner_.<span class="me1">end</span><span class="br0">(</span><span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
      <span class="br0">}</span>
    <span class="br0">}</span>
 
    <span class="kw4">constexpr</span> <span class="kw4">auto</span> end<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span>
      requires range<span class="sy1">&lt;</span><span class="kw4">const</span> InnerView<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
               regular_invocable<span class="sy1">&lt;</span><span class="kw4">const</span> F<span class="sy3">&amp;</span>, <span class="coMULTI">/*REPEAT*/</span><span class="br0">(</span>range_reference_t<span class="sy1">&lt;</span><span class="kw4">const</span> V<span class="sy1">&gt;</span>, N<span class="br0">)</span>...<span class="sy1">&gt;</span> <span class="br0">{</span>
      <span class="kw1">if</span> <span class="kw4">constexpr</span> <span class="br0">(</span>common_range<span class="sy1">&lt;</span><span class="kw4">const</span> InnerView<span class="sy1">&gt;</span><span class="br0">)</span> <span class="br0">{</span>
        <span class="kw1">return</span> iterator<span class="sy1">&lt;</span><span class="kw2">true</span><span class="sy1">&gt;</span><span class="br0">(</span><span class="sy2">*</span>this, inner_.<span class="me1">end</span><span class="br0">(</span><span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
      <span class="br0">}</span> <span class="kw1">else</span> <span class="br0">{</span>
        <span class="kw1">return</span> sentinel<span class="sy1">&lt;</span><span class="kw2">true</span><span class="sy1">&gt;</span><span class="br0">(</span>inner_.<span class="me1">end</span><span class="br0">(</span><span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
      <span class="br0">}</span>
    <span class="br0">}</span>
 
    <span class="kw4">constexpr</span> <span class="kw4">auto</span> size<span class="br0">(</span><span class="br0">)</span> requires sized_range<span class="sy1">&lt;</span>InnerView<span class="sy1">&gt;</span> <span class="br0">{</span>
      <span class="kw1">return</span> inner_.<span class="me1">size</span><span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>
    <span class="br0">}</span>
 
    <span class="kw4">constexpr</span> <span class="kw4">auto</span> size<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span> requires sized_range<span class="sy1">&lt;</span><span class="kw4">const</span> InnerView<span class="sy1">&gt;</span> <span class="br0">{</span>
      <span class="kw1">return</span> inner_.<span class="me1">size</span><span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>
    <span class="br0">}</span>
  <span class="br0">}</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<h4><span class="mw-headline" id="Class_template_std::ranges::adjacent_transform_view::iterator">Class template <span class="t-lc">std::ranges::adjacent_transform_view::iterator</span></span></h4>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">namespace</span> std<span class="sy4">::</span><span class="me2">ranges</span> <span class="br0">{</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span>forward_range V, copy_constructible F, size_t N<span class="sy1">&gt;</span>
    requires view<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> <span class="br0">(</span>N <span class="sy1">&gt;</span> <span class="nu0">0</span><span class="br0">)</span> <span class="sy3">&amp;&amp;</span> is_object_v<span class="sy1">&lt;</span>F<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
             regular_invocable<span class="sy1">&lt;</span>F<span class="sy3">&amp;</span>, <span class="coMULTI">/*REPEAT*/</span><span class="br0">(</span>range_reference_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span>, N<span class="br0">)</span>...<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
             <span class="coMULTI">/*can-reference*/</span><span class="sy1">&lt;</span>invoke_result_t<span class="sy1">&lt;</span>F<span class="sy3">&amp;</span>,
               <span class="coMULTI">/*REPEAT*/</span><span class="br0">(</span>range_reference_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span>, N<span class="br0">)</span>...<span class="sy1">&gt;&gt;</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw4">bool</span> Const<span class="sy1">&gt;</span>
  <span class="kw1">class</span> adjacent_transform_view<span class="sy1">&lt;</span>F, V...<span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">iterator</span> <span class="br0">{</span>
    <span class="kw1">using</span> Parent <span class="sy1">=</span> <span class="coMULTI">/*maybe-const*/</span><span class="sy1">&lt;</span>Const, adjacent_transform_view<span class="sy1">&gt;</span><span class="sy4">;</span>  <span class="co1">// exposition only</span>
    <span class="kw1">using</span> Base <span class="sy1">=</span> <span class="coMULTI">/*maybe-const*/</span><span class="sy1">&lt;</span>Const, V<span class="sy1">&gt;</span><span class="sy4">;</span>                          <span class="co1">// exposition only</span>
    Parent<span class="sy2">*</span> parent_ <span class="sy1">=</span> nullptr<span class="sy4">;</span>                                       <span class="co1">// exposition only</span>
    <span class="coMULTI">/*inner-iterator*/</span><span class="sy1">&lt;</span>Const<span class="sy1">&gt;</span> inner_<span class="sy4">;</span>                                <span class="co1">// exposition only</span>
 
    <span class="kw4">constexpr</span> iterator<span class="br0">(</span>Parent<span class="sy3">&amp;</span> parent,
      <span class="coMULTI">/*inner-iterator*/</span><span class="sy1">&lt;</span>Const<span class="sy1">&gt;</span> inner<span class="br0">)</span><span class="sy4">;</span>    <span class="co1">// exposition only</span>
 
  <span class="kw1">public</span><span class="sy4">:</span>
    <span class="kw1">using</span> iterator_category <span class="sy1">=</span> <span class="coMULTI">/* see description */</span><span class="sy4">;</span>
    <span class="kw1">using</span> iterator_concept  <span class="sy1">=</span> <span class="kw1">typename</span> <span class="coMULTI">/*inner-iterator*/</span><span class="sy1">&lt;</span>Const<span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">iterator_concept</span><span class="sy4">;</span>
    <span class="kw1">using</span> value_type <span class="sy1">=</span>
      remove_cvref_t<span class="sy1">&lt;</span>invoke_result_t<span class="sy1">&lt;</span><span class="coMULTI">/*maybe-const*/</span><span class="sy1">&lt;</span>Const, F<span class="sy1">&gt;</span><span class="sy3">&amp;</span>,
                                     <span class="coMULTI">/*REPEAT*/</span><span class="br0">(</span>range_reference_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span>, N<span class="br0">)</span>...<span class="sy1">&gt;&gt;</span><span class="sy4">;</span>
    <span class="kw1">using</span> difference_type <span class="sy1">=</span> range_difference_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span><span class="sy4">;</span>
 
    iterator<span class="br0">(</span><span class="br0">)</span> <span class="sy1">=</span> <span class="kw1">default</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> iterator<span class="br0">(</span>iterator<span class="sy1">&lt;</span><span class="sy3">!</span>Const<span class="sy1">&gt;</span> i<span class="br0">)</span>
      requires Const <span class="sy3">&amp;&amp;</span> convertible_to<span class="sy1">&lt;</span><span class="coMULTI">/*inner-iterator*/</span><span class="sy1">&lt;</span><span class="kw2">false</span><span class="sy1">&gt;</span>,
        <span class="coMULTI">/*inner-iterator*/</span><span class="sy1">&lt;</span>Const<span class="sy1">&gt;&gt;</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> decltype<span class="br0">(</span><span class="kw4">auto</span><span class="br0">)</span> operator<span class="sy2">*</span><span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span> <span class="kw1">noexcept</span><span class="br0">(</span><span class="coMULTI">/* see description */</span><span class="br0">)</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> iterator<span class="sy3">&amp;</span> operator<span class="sy2">++</span><span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> iterator operator<span class="sy2">++</span><span class="br0">(</span><span class="kw4">int</span><span class="br0">)</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> iterator<span class="sy3">&amp;</span> operator<span class="sy2">--</span><span class="br0">(</span><span class="br0">)</span> requires bidirectional_range<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> iterator operator<span class="sy2">--</span><span class="br0">(</span><span class="kw4">int</span><span class="br0">)</span> requires bidirectional_range<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> iterator<span class="sy3">&amp;</span> operator<span class="sy2">+</span><span class="sy1">=</span><span class="br0">(</span>difference_type x<span class="br0">)</span> requires random_access_range<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> iterator<span class="sy3">&amp;</span> operator<span class="sy2">-</span><span class="sy1">=</span><span class="br0">(</span>difference_type x<span class="br0">)</span> requires random_access_range<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> decltype<span class="br0">(</span><span class="kw4">auto</span><span class="br0">)</span> operator<span class="br0">[</span><span class="br0">]</span><span class="br0">(</span>difference_type n<span class="br0">)</span> <span class="kw4">const</span>
      requires random_access_range<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span><span class="sy4">;</span>
 
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> operator<span class="sy1">==</span><span class="br0">(</span><span class="kw4">const</span> iterator<span class="sy3">&amp;</span> x, <span class="kw4">const</span> iterator<span class="sy3">&amp;</span> y<span class="br0">)</span><span class="sy4">;</span>
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> operator<span class="sy1">&lt;</span><span class="br0">(</span><span class="kw4">const</span> iterator<span class="sy3">&amp;</span> x, <span class="kw4">const</span> iterator<span class="sy3">&amp;</span> y<span class="br0">)</span>
      requires random_access_range<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span><span class="sy4">;</span>
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> operator<span class="sy1">&gt;</span><span class="br0">(</span><span class="kw4">const</span> iterator<span class="sy3">&amp;</span> x, <span class="kw4">const</span> iterator<span class="sy3">&amp;</span> y<span class="br0">)</span>
      requires random_access_range<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span><span class="sy4">;</span>
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> operator<span class="sy1">&lt;=</span><span class="br0">(</span><span class="kw4">const</span> iterator<span class="sy3">&amp;</span> x, <span class="kw4">const</span> iterator<span class="sy3">&amp;</span> y<span class="br0">)</span>
      requires random_access_range<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span><span class="sy4">;</span>
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> operator<span class="sy1">&gt;=</span><span class="br0">(</span><span class="kw4">const</span> iterator<span class="sy3">&amp;</span> x, <span class="kw4">const</span> iterator<span class="sy3">&amp;</span> y<span class="br0">)</span>
      requires random_access_range<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span><span class="sy4">;</span>
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> <span class="kw4">auto</span> operator<span class="sy1">&lt;=&gt;</span><span class="br0">(</span><span class="kw4">const</span> iterator<span class="sy3">&amp;</span> x, <span class="kw4">const</span> iterator<span class="sy3">&amp;</span> y<span class="br0">)</span>
      requires random_access_range<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> three_way_comparable<span class="sy1">&lt;</span>
        <span class="coMULTI">/*inner-iterator*/</span><span class="sy1">&lt;</span>Const<span class="sy1">&gt;&gt;</span><span class="sy4">;</span>
 
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> iterator operator<span class="sy2">+</span><span class="br0">(</span><span class="kw4">const</span> iterator<span class="sy3">&amp;</span> i, difference_type n<span class="br0">)</span>
      requires random_access_range<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span><span class="sy4">;</span>
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> iterator operator<span class="sy2">+</span><span class="br0">(</span>difference_type n, <span class="kw4">const</span> iterator<span class="sy3">&amp;</span> i<span class="br0">)</span>
      requires random_access_range<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span><span class="sy4">;</span>
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> iterator operator<span class="sy2">-</span><span class="br0">(</span><span class="kw4">const</span> iterator<span class="sy3">&amp;</span> i, difference_type n<span class="br0">)</span>
      requires random_access_range<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span><span class="sy4">;</span>
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> difference_type operator<span class="sy2">-</span><span class="br0">(</span><span class="kw4">const</span> iterator<span class="sy3">&amp;</span> x, <span class="kw4">const</span> iterator<span class="sy3">&amp;</span> y<span class="br0">)</span>
      requires sized_sentinel_for<span class="sy1">&lt;</span><span class="coMULTI">/*inner-iterator*/</span><span class="sy1">&lt;</span>Const<span class="sy1">&gt;</span>, <span class="coMULTI">/*inner-iterator*/</span><span class="sy1">&lt;</span>Const<span class="sy1">&gt;&gt;</span><span class="sy4">;</span>
  <span class="br0">}</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<h4><span class="mw-headline" id="Class_template_std::ranges::adjacent_transform_view::sentinel">Class template <span class="t-lc">std::ranges::adjacent_transform_view::sentinel</span></span></h4>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">namespace</span> std<span class="sy4">::</span><span class="me2">ranges</span> <span class="br0">{</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span>forward_range V, copy_constructible F, size_t N<span class="sy1">&gt;</span>
    requires view<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> <span class="br0">(</span>N <span class="sy1">&gt;</span> <span class="nu0">0</span><span class="br0">)</span> <span class="sy3">&amp;&amp;</span> is_object_v<span class="sy1">&lt;</span>F<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
             regular_invocable<span class="sy1">&lt;</span>F<span class="sy3">&amp;</span>, <span class="coMULTI">/*REPEAT*/</span><span class="br0">(</span>range_reference_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span>, N<span class="br0">)</span>...<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
             <span class="coMULTI">/*can-reference*/</span><span class="sy1">&lt;</span>invoke_result_t<span class="sy1">&lt;</span>F<span class="sy3">&amp;</span>,
               <span class="coMULTI">/*REPEAT*/</span><span class="br0">(</span>range_reference_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span>, N<span class="br0">)</span>...<span class="sy1">&gt;&gt;</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw4">bool</span> Const<span class="sy1">&gt;</span>
  <span class="kw1">class</span> adjacent_transform_view<span class="sy1">&lt;</span>V, F, N<span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">sentinel</span> <span class="br0">{</span>
    <span class="coMULTI">/*inner-sentinel*/</span><span class="sy1">&lt;</span>Const<span class="sy1">&gt;</span> inner_<span class="sy4">;</span>                               <span class="co1">// exposition only</span>
    <span class="kw4">constexpr</span> <span class="kw1">explicit</span> sentinel<span class="br0">(</span><span class="coMULTI">/*inner-sentinel*/</span><span class="sy1">&lt;</span>Const<span class="sy1">&gt;</span> inner<span class="br0">)</span><span class="sy4">;</span>   <span class="co1">// exposition only</span>
 
  <span class="kw1">public</span><span class="sy4">:</span>
    sentinel<span class="br0">(</span><span class="br0">)</span> <span class="sy1">=</span> <span class="kw1">default</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> sentinel<span class="br0">(</span>sentinel<span class="sy1">&lt;</span><span class="sy3">!</span>Const<span class="sy1">&gt;</span> i<span class="br0">)</span>
      requires Const <span class="sy3">&amp;&amp;</span> convertible_to<span class="sy1">&lt;</span><span class="coMULTI">/*inner-sentinel*/</span><span class="sy1">&lt;</span><span class="kw2">false</span><span class="sy1">&gt;</span>,
                                       <span class="coMULTI">/*inner-sentinel*/</span><span class="sy1">&lt;</span>Const<span class="sy1">&gt;&gt;</span><span class="sy4">;</span>
    <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw4">bool</span> OtherConst<span class="sy1">&gt;</span>
      requires sentinel_for<span class="sy1">&lt;</span><span class="coMULTI">/*inner-sentinel*/</span><span class="sy1">&lt;</span>Const<span class="sy1">&gt;</span>, <span class="coMULTI">/*inner-iterator*/</span><span class="sy1">&lt;</span>OtherConst<span class="sy1">&gt;&gt;</span>
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> operator<span class="sy1">==</span><span class="br0">(</span><span class="kw4">const</span> iterator<span class="sy1">&lt;</span>OtherConst<span class="sy1">&gt;</span><span class="sy3">&amp;</span> x, <span class="kw4">const</span> sentinel<span class="sy3">&amp;</span> y<span class="br0">)</span><span class="sy4">;</span>
 
    <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw4">bool</span> OtherConst<span class="sy1">&gt;</span>
      requires sized_sentinel_for<span class="sy1">&lt;</span><span class="coMULTI">/*inner-sentinel*/</span><span class="sy1">&lt;</span>Const<span class="sy1">&gt;</span>,
                                  <span class="coMULTI">/*inner-iterator*/</span><span class="sy1">&lt;</span>OtherConst<span class="sy1">&gt;&gt;</span>
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> range_difference_t<span class="sy1">&lt;</span><span class="coMULTI">/*maybe-const*/</span><span class="sy1">&lt;</span>OtherConst, InnerView<span class="sy1">&gt;&gt;</span>
      operator<span class="sy2">-</span><span class="br0">(</span><span class="kw4">const</span> iterator<span class="sy1">&lt;</span>OtherConst<span class="sy1">&gt;</span><span class="sy3">&amp;</span> x, <span class="kw4">const</span> sentinel<span class="sy3">&amp;</span> y<span class="br0">)</span><span class="sy4">;</span>
 
    <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw4">bool</span> OtherConst<span class="sy1">&gt;</span>
      requires sized_sentinel_for<span class="sy1">&lt;</span><span class="coMULTI">/*inner-sentinel*/</span><span class="sy1">&lt;</span>Const<span class="sy1">&gt;</span>,
                                  <span class="coMULTI">/*inner-iterator*/</span><span class="sy1">&lt;</span>OtherConst<span class="sy1">&gt;&gt;</span>
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> range_difference_t<span class="sy1">&lt;</span><span class="coMULTI">/*maybe-const*/</span><span class="sy1">&lt;</span>OtherConst, InnerView<span class="sy1">&gt;&gt;</span>
      operator<span class="sy2">-</span><span class="br0">(</span><span class="kw4">const</span> sentinel<span class="sy3">&amp;</span> x, <span class="kw4">const</span> iterator<span class="sy1">&lt;</span>OtherConst<span class="sy1">&gt;</span><span class="sy3">&amp;</span> y<span class="br0">)</span><span class="sy4">;</span>
  <span class="br0">}</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<h4><span class="mw-headline" id="Class_template_std::ranges::chunk_view_for_input_ranges">Class template <span class="t-lc">std::ranges::chunk_view</span> for input ranges</span></h4>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">namespace</span> std<span class="sy4">::</span><span class="me2">ranges</span> <span class="br0">{</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> I<span class="sy1">&gt;</span>
  <span class="kw4">constexpr</span> I <span class="coMULTI">/*div-ceil*/</span><span class="br0">(</span>I num, I denom<span class="br0">)</span> <span class="br0">{</span>              <span class="co1">// exposition only</span>
    I r <span class="sy1">=</span> num <span class="sy2">/</span> denom<span class="sy4">;</span>
    <span class="kw1">if</span> <span class="br0">(</span>num <span class="sy2">%</span> denom<span class="br0">)</span>
      <span class="sy2">++</span>r<span class="sy4">;</span>
    <span class="kw1">return</span> r<span class="sy4">;</span>
  <span class="br0">}</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span>view V<span class="sy1">&gt;</span>
    requires input_range<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span>
  <span class="kw1">class</span> chunk_view <span class="sy4">:</span> <span class="kw1">public</span> view_interface<span class="sy1">&lt;</span>chunk_view<span class="sy1">&lt;</span>V<span class="sy1">&gt;&gt;</span> <span class="br0">{</span>
    V base_ <span class="sy1">=</span> V<span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>                                        <span class="co1">// exposition only</span>
    range_difference_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> n_ <span class="sy1">=</span> <span class="nu0">0</span><span class="sy4">;</span>                         <span class="co1">// exposition only</span>
    range_difference_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> remainder_ <span class="sy1">=</span> <span class="nu0">0</span><span class="sy4">;</span>                 <span class="co1">// exposition only</span>
 
    <span class="coMULTI">/*non-propagating-cache*/</span><span class="sy1">&lt;</span>iterator_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;&gt;</span> current_<span class="sy4">;</span>    <span class="co1">// exposition only</span>
 
    <span class="co1">// class chunk_view::/*outer-iterator*/</span>
    <span class="kw1">class</span> <span class="coMULTI">/*outer-iterator*/</span><span class="sy4">;</span>                             <span class="co1">// exposition only</span>
 
    <span class="co1">// class chunk_view::/*inner-iterator*/</span>
    <span class="kw1">class</span> <span class="coMULTI">/*inner-iterator*/</span><span class="sy4">;</span>                             <span class="co1">// exposition only</span>
 
  <span class="kw1">public</span><span class="sy4">:</span>
    chunk_view<span class="br0">(</span><span class="br0">)</span> requires default_initializable<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> <span class="sy1">=</span> <span class="kw1">default</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> <span class="kw1">explicit</span> chunk_view<span class="br0">(</span>V base, range_difference_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> n<span class="br0">)</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> V base<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span> <span class="sy3">&amp;</span> requires copy_constructible<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> <span class="br0">{</span> <span class="kw1">return</span> base_<span class="sy4">;</span> <span class="br0">}</span>
    <span class="kw4">constexpr</span> V base<span class="br0">(</span><span class="br0">)</span> <span class="sy3">&amp;&amp;</span> <span class="br0">{</span> <span class="kw1">return</span> std<span class="sy4">::</span><span class="me2">move</span><span class="br0">(</span>base_<span class="br0">)</span><span class="sy4">;</span> <span class="br0">}</span>
 
    <span class="kw4">constexpr</span> <span class="coMULTI">/*outer-iterator*/</span> begin<span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> default_sentinel_t end<span class="br0">(</span><span class="br0">)</span> <span class="kw1">noexcept</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> <span class="kw4">auto</span> size<span class="br0">(</span><span class="br0">)</span> requires sized_range<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> <span class="kw4">auto</span> size<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span> requires sized_range<span class="sy1">&lt;</span><span class="kw4">const</span> V<span class="sy1">&gt;</span><span class="sy4">;</span>
  <span class="br0">}</span><span class="sy4">;</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> R<span class="sy1">&gt;</span>
    chunk_view<span class="br0">(</span>R<span class="sy3">&amp;&amp;</span> r, range_difference_t<span class="sy1">&lt;</span>R<span class="sy1">&gt;</span><span class="br0">)</span> <span class="sy2">-</span><span class="sy1">&gt;</span> chunk_view<span class="sy1">&lt;</span><a href="../ranges/all_view.html"><span class="kw2919">views::<span class="me2">all_t</span></span></a><span class="sy1">&lt;</span>R<span class="sy1">&gt;&gt;</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<h4><span class="mw-headline" id="Class_std::ranges::chunk_view::outer_iterator_for_input_ranges">Class <span class="t-lc">std::ranges::chunk_view::outer_iterator</span> for input ranges</span></h4>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">namespace</span> std<span class="sy4">::</span><span class="me2">ranges</span> <span class="br0">{</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span>view V<span class="sy1">&gt;</span>
    requires input_range<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span>
  <span class="kw1">class</span> chunk_view<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span><span class="sy4">::</span><span class="coMULTI">/*outer-iterator*/</span> <span class="br0">{</span>
    chunk_view<span class="sy2">*</span> parent_<span class="sy4">;</span>                                        <span class="co1">// exposition only</span>
 
    <span class="kw4">constexpr</span> <span class="kw1">explicit</span> <span class="coMULTI">/*outer-iterator*/</span><span class="br0">(</span>chunk_view<span class="sy3">&amp;</span> parent<span class="br0">)</span><span class="sy4">;</span>  <span class="co1">// exposition only</span>
 
  <span class="kw1">public</span><span class="sy4">:</span>
    <span class="kw1">using</span> iterator_concept <span class="sy1">=</span> input_iterator_tag<span class="sy4">;</span>
    <span class="kw1">using</span> difference_type  <span class="sy1">=</span> range_difference_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span><span class="sy4">;</span>
 
    <span class="co1">// class chunk_view::/*outer-iterator*/::value_type</span>
    <span class="kw1">struct</span> value_type<span class="sy4">;</span>
 
    <span class="coMULTI">/*outer-iterator*/</span><span class="br0">(</span><span class="coMULTI">/*outer-iterator*/</span><span class="sy3">&amp;&amp;</span><span class="br0">)</span> <span class="sy1">=</span> <span class="kw1">default</span><span class="sy4">;</span>
    <span class="coMULTI">/*outer-iterator*/</span>r<span class="sy3">&amp;</span> operator<span class="sy1">=</span><span class="br0">(</span><span class="coMULTI">/*outer-iterator*/</span><span class="sy3">&amp;&amp;</span><span class="br0">)</span> <span class="sy1">=</span> <span class="kw1">default</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> value_type operator<span class="sy2">*</span><span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> <span class="coMULTI">/*outer-iterator*/</span><span class="sy3">&amp;</span> operator<span class="sy2">++</span><span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> <span class="kw4">void</span> operator<span class="sy2">++</span><span class="br0">(</span><span class="kw4">int</span><span class="br0">)</span><span class="sy4">;</span>
 
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> operator<span class="sy1">==</span><span class="br0">(</span><span class="kw4">const</span> <span class="coMULTI">/*outer-iterator*/</span><span class="sy3">&amp;</span> x, default_sentinel_t<span class="br0">)</span><span class="sy4">;</span>
 
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> difference_type operator<span class="sy2">-</span><span class="br0">(</span>default_sentinel_t y,
                                               <span class="kw4">const</span> <span class="coMULTI">/*outer-iterator*/</span><span class="sy3">&amp;</span> x<span class="br0">)</span>
      requires sized_sentinel_for<span class="sy1">&lt;</span>sentinel_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span>, iterator_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;&gt;</span><span class="sy4">;</span>
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> difference_type operator<span class="sy2">-</span><span class="br0">(</span><span class="kw4">const</span> <span class="coMULTI">/*outer-iterator*/</span><span class="sy3">&amp;</span> x,
                                               default_sentinel_t y<span class="br0">)</span>
      requires sized_sentinel_for<span class="sy1">&lt;</span>sentinel_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span>, iterator_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;&gt;</span><span class="sy4">;</span>
  <span class="br0">}</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<h4><span class="mw-headline" id="Class_std::ranges::chunk_view::outer_iterator::value_type_for_input_ranges">Class <span class="t-lc">std::ranges::chunk_view::outer_iterator::value_type</span> for input ranges</span></h4>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">namespace</span> std<span class="sy4">::</span><span class="me2">ranges</span> <span class="br0">{</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span>view V<span class="sy1">&gt;</span>
    requires input_range<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span>
  <span class="kw1">struct</span> chunk_view<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span><span class="sy4">::</span><span class="coMULTI">/*outer-iterator*/</span><span class="sy4">::</span><span class="me2">value_type</span>
  <span class="sy4">:</span> view_interface<span class="sy1">&lt;</span>value_type<span class="sy1">&gt;</span> <span class="br0">{</span>
  <span class="kw1">private</span><span class="sy4">:</span>
    chunk_view<span class="sy2">*</span> parent_<span class="sy4">;</span>                                        <span class="co1">// exposition only</span>
 
    <span class="kw4">constexpr</span> <span class="kw1">explicit</span> value_type<span class="br0">(</span>chunk_view<span class="sy3">&amp;</span> parent<span class="br0">)</span><span class="sy4">;</span>          <span class="co1">// exposition only</span>
 
  <span class="kw1">public</span><span class="sy4">:</span>
    <span class="kw4">constexpr</span> <span class="coMULTI">/*inner-iterator*/</span> begin<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span> <span class="kw1">noexcept</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> default_sentinel_t end<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span> <span class="kw1">noexcept</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> <span class="kw4">auto</span> size<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span>
      requires sized_sentinel_for<span class="sy1">&lt;</span>sentinel_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span>, iterator_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;&gt;</span><span class="sy4">;</span>
  <span class="br0">}</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<h4><span class="mw-headline" id="Class_std::ranges::chunk_view::inner_iterator_for_input_ranges">Class <span class="t-lc">std::ranges::chunk_view::inner_iterator</span> for input ranges</span></h4>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">namespace</span> std<span class="sy4">::</span><span class="me2">ranges</span> <span class="br0">{</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span>view V<span class="sy1">&gt;</span>
    requires input_range<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span>
  <span class="kw1">class</span> chunk_view<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span><span class="sy4">::</span><span class="coMULTI">/*inner-iterator*/</span> <span class="br0">{</span>
    chunk_view<span class="sy2">*</span> parent_<span class="sy4">;</span>                                                <span class="co1">// exposition only</span>
 
    <span class="kw4">constexpr</span> <span class="kw1">explicit</span> <span class="coMULTI">/*inner-iterator*/</span><span class="br0">(</span>chunk_view<span class="sy3">&amp;</span> parent<span class="br0">)</span> <span class="kw1">noexcept</span><span class="sy4">;</span>     <span class="co1">// exposition only</span>
 
  <span class="kw1">public</span><span class="sy4">:</span>
    <span class="kw1">using</span> iterator_concept <span class="sy1">=</span> input_iterator_tag<span class="sy4">;</span>
    <span class="kw1">using</span> difference_type <span class="sy1">=</span> range_difference_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span><span class="sy4">;</span>
    <span class="kw1">using</span> value_type <span class="sy1">=</span> range_value_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span><span class="sy4">;</span>
 
    <span class="coMULTI">/*inner-iterator*/</span><span class="br0">(</span><span class="coMULTI">/*inner-iterator*/</span><span class="sy3">&amp;&amp;</span><span class="br0">)</span> <span class="sy1">=</span> <span class="kw1">default</span><span class="sy4">;</span>
    <span class="coMULTI">/*inner-iterator*/</span><span class="sy3">&amp;</span> operator<span class="sy1">=</span><span class="br0">(</span><span class="coMULTI">/*inner-iterator*/</span><span class="sy3">&amp;&amp;</span><span class="br0">)</span> <span class="sy1">=</span> <span class="kw1">default</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> <span class="kw4">const</span> iterator_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span><span class="sy3">&amp;</span> base<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span> <span class="sy3">&amp;</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> range_reference_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> operator<span class="sy2">*</span><span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> <span class="coMULTI">/*inner-iterator*/</span><span class="sy3">&amp;</span> operator<span class="sy2">++</span><span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> <span class="kw4">void</span> operator<span class="sy2">++</span><span class="br0">(</span><span class="kw4">int</span><span class="br0">)</span><span class="sy4">;</span>
 
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> operator<span class="sy1">==</span><span class="br0">(</span><span class="kw4">const</span> <span class="coMULTI">/*inner-iterator*/</span><span class="sy3">&amp;</span> x, default_sentinel_t<span class="br0">)</span><span class="sy4">;</span>
 
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> difference_type operator<span class="sy2">-</span><span class="br0">(</span>default_sentinel_t y,
                                               <span class="kw4">const</span> <span class="coMULTI">/*inner-iterator*/</span><span class="sy3">&amp;</span> x<span class="br0">)</span>
      requires sized_sentinel_for<span class="sy1">&lt;</span>sentinel_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span>, iterator_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;&gt;</span><span class="sy4">;</span>
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> difference_type operator<span class="sy2">-</span><span class="br0">(</span><span class="kw4">const</span> <span class="coMULTI">/*inner-iterator*/</span><span class="sy3">&amp;</span> x,
                                               default_sentinel_t y<span class="br0">)</span>
      requires sized_sentinel_for<span class="sy1">&lt;</span>sentinel_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span>, iterator_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;&gt;</span><span class="sy4">;</span>
  <span class="br0">}</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<h4><span class="mw-headline" id="Class_template_std::ranges::chunk_view_for_forward_ranges">Class template <span class="t-lc">std::ranges::chunk_view</span> for forward ranges</span></h4>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">namespace</span> std<span class="sy4">::</span><span class="me2">ranges</span> <span class="br0">{</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span>view V<span class="sy1">&gt;</span>
    requires forward_range<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span>
  <span class="kw1">class</span> chunk_view<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> <span class="sy4">:</span> <span class="kw1">public</span> view_interface<span class="sy1">&lt;</span>chunk_view<span class="sy1">&lt;</span>V<span class="sy1">&gt;&gt;</span> <span class="br0">{</span>
    V base_ <span class="sy1">=</span> V<span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>                      <span class="co1">// exposition only</span>
    range_difference_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> n_ <span class="sy1">=</span> <span class="nu0">0</span><span class="sy4">;</span>       <span class="co1">// exposition only</span>
 
    <span class="co1">// class template chunk_view::iterator</span>
    <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw4">bool</span><span class="sy1">&gt;</span> <span class="kw1">class</span> iterator<span class="sy4">;</span>      <span class="co1">// exposition only</span>
 
  <span class="kw1">public</span><span class="sy4">:</span>
    chunk_view<span class="br0">(</span><span class="br0">)</span> requires default_initializable<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> <span class="sy1">=</span> <span class="kw1">default</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> <span class="kw1">explicit</span> chunk_view<span class="br0">(</span>V base, range_difference_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> n<span class="br0">)</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> V base<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span> <span class="sy3">&amp;</span> requires copy_constructible<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> <span class="br0">{</span> <span class="kw1">return</span> base_<span class="sy4">;</span> <span class="br0">}</span>
    <span class="kw4">constexpr</span> V base<span class="br0">(</span><span class="br0">)</span> <span class="sy3">&amp;&amp;</span> <span class="br0">{</span> <span class="kw1">return</span> std<span class="sy4">::</span><span class="me2">move</span><span class="br0">(</span>base_<span class="br0">)</span><span class="sy4">;</span> <span class="br0">}</span>
 
    <span class="kw4">constexpr</span> <span class="kw4">auto</span> begin<span class="br0">(</span><span class="br0">)</span> requires <span class="br0">(</span><span class="sy3">!</span><span class="coMULTI">/*simple-view*/</span><span class="sy1">&lt;</span>V<span class="sy1">&gt;</span><span class="br0">)</span> <span class="br0">{</span>
      <span class="kw1">return</span> iterator<span class="sy1">&lt;</span><span class="kw2">false</span><span class="sy1">&gt;</span><span class="br0">(</span>this, <a href="../../../http:/en.cppreference.com/w/cpp/ranges-ranges-placeholder/begin"><span class="kw2885">ranges::<span class="me2">begin</span></span></a><span class="br0">(</span>base_<span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
    <span class="br0">}</span>
 
    <span class="kw4">constexpr</span> <span class="kw4">auto</span> begin<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span> requires forward_range<span class="sy1">&lt;</span><span class="kw4">const</span> V<span class="sy1">&gt;</span> <span class="br0">{</span>
      <span class="kw1">return</span> iterator<span class="sy1">&lt;</span><span class="kw2">true</span><span class="sy1">&gt;</span><span class="br0">(</span>this, <a href="../../../http:/en.cppreference.com/w/cpp/ranges-ranges-placeholder/begin"><span class="kw2885">ranges::<span class="me2">begin</span></span></a><span class="br0">(</span>base_<span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
    <span class="br0">}</span>
 
    <span class="kw4">constexpr</span> <span class="kw4">auto</span> end<span class="br0">(</span><span class="br0">)</span> requires <span class="br0">(</span><span class="sy3">!</span><span class="coMULTI">/*simple-view*/</span><span class="sy1">&lt;</span>V<span class="sy1">&gt;</span><span class="br0">)</span> <span class="br0">{</span>
      <span class="kw1">if</span> <span class="kw4">constexpr</span> <span class="br0">(</span>common_range<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> sized_range<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span><span class="br0">)</span> <span class="br0">{</span>
        <span class="kw4">auto</span> missing <span class="sy1">=</span> <span class="br0">(</span>n_ <span class="sy2">-</span> <a href="../iterator/ranges/distance.html"><span class="kw3145">ranges::<span class="me2">distance</span></span></a><span class="br0">(</span>base_<span class="br0">)</span> <span class="sy2">%</span> n_<span class="br0">)</span> <span class="sy2">%</span> n_<span class="sy4">;</span>
        <span class="kw1">return</span> iterator<span class="sy1">&lt;</span><span class="kw2">false</span><span class="sy1">&gt;</span><span class="br0">(</span>this, <a href="../../../http:/en.cppreference.com/w/cpp/ranges-ranges-placeholder/end"><span class="kw2887">ranges::<span class="me2">end</span></span></a><span class="br0">(</span>base_<span class="br0">)</span>, missing<span class="br0">)</span><span class="sy4">;</span>
      <span class="br0">}</span> <span class="kw1">else</span> <span class="kw1">if</span> <span class="kw4">constexpr</span> <span class="br0">(</span>common_range<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> <span class="sy3">!</span>bidirectional_range<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span><span class="br0">)</span> <span class="br0">{</span>
        <span class="kw1">return</span> iterator<span class="sy1">&lt;</span><span class="kw2">false</span><span class="sy1">&gt;</span><span class="br0">(</span>this, <a href="../../../http:/en.cppreference.com/w/cpp/ranges-ranges-placeholder/end"><span class="kw2887">ranges::<span class="me2">end</span></span></a><span class="br0">(</span>base_<span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
      <span class="br0">}</span> <span class="kw1">else</span> <span class="br0">{</span>
        <span class="kw1">return</span> default_sentinel<span class="sy4">;</span>
      <span class="br0">}</span>
    <span class="br0">}</span>
 
    <span class="kw4">constexpr</span> <span class="kw4">auto</span> end<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span> requires forward_range<span class="sy1">&lt;</span><span class="kw4">const</span> V<span class="sy1">&gt;</span> <span class="br0">{</span>
      <span class="kw1">if</span> <span class="kw4">constexpr</span> <span class="br0">(</span>common_range<span class="sy1">&lt;</span><span class="kw4">const</span> V<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> sized_range<span class="sy1">&lt;</span><span class="kw4">const</span> V<span class="sy1">&gt;</span><span class="br0">)</span> <span class="br0">{</span>
        <span class="kw4">auto</span> missing <span class="sy1">=</span> <span class="br0">(</span>n_ <span class="sy2">-</span> <a href="../iterator/ranges/distance.html"><span class="kw3145">ranges::<span class="me2">distance</span></span></a><span class="br0">(</span>base_<span class="br0">)</span> <span class="sy2">%</span> n_<span class="br0">)</span> <span class="sy2">%</span> n_<span class="sy4">;</span>
        <span class="kw1">return</span> iterator<span class="sy1">&lt;</span><span class="kw2">true</span><span class="sy1">&gt;</span><span class="br0">(</span>this, <a href="../../../http:/en.cppreference.com/w/cpp/ranges-ranges-placeholder/end"><span class="kw2887">ranges::<span class="me2">end</span></span></a><span class="br0">(</span>base_<span class="br0">)</span>, missing<span class="br0">)</span><span class="sy4">;</span>
      <span class="br0">}</span> <span class="kw1">else</span> <span class="kw1">if</span> <span class="kw4">constexpr</span> <span class="br0">(</span>common_range<span class="sy1">&lt;</span><span class="kw4">const</span> V<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> <span class="sy3">!</span>bidirectional_range<span class="sy1">&lt;</span><span class="kw4">const</span> V<span class="sy1">&gt;</span><span class="br0">)</span> <span class="br0">{</span>
        <span class="kw1">return</span> iterator<span class="sy1">&lt;</span><span class="kw2">true</span><span class="sy1">&gt;</span><span class="br0">(</span>this, <a href="../../../http:/en.cppreference.com/w/cpp/ranges-ranges-placeholder/end"><span class="kw2887">ranges::<span class="me2">end</span></span></a><span class="br0">(</span>base_<span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
      <span class="br0">}</span> <span class="kw1">else</span> <span class="br0">{</span>
        <span class="kw1">return</span> default_sentinel<span class="sy4">;</span>
      <span class="br0">}</span>
    <span class="br0">}</span>
 
    <span class="kw4">constexpr</span> <span class="kw4">auto</span> size<span class="br0">(</span><span class="br0">)</span> requires sized_range<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> <span class="kw4">auto</span> size<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span> requires sized_range<span class="sy1">&lt;</span><span class="kw4">const</span> V<span class="sy1">&gt;</span><span class="sy4">;</span>
  <span class="br0">}</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<h4><span class="mw-headline" id="Class_template_std::ranges::chunk_view::iterator_for_forward_ranges">Class template <span class="t-lc">std::ranges::chunk_view::iterator</span> for forward ranges</span></h4>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">namespace</span> std<span class="sy4">::</span><span class="me2">ranges</span> <span class="br0">{</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span>view V<span class="sy1">&gt;</span>
    requires forward_range<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw4">bool</span> Const<span class="sy1">&gt;</span>
  <span class="kw1">class</span> chunk_view<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">iterator</span> <span class="br0">{</span>
    <span class="kw1">using</span> Parent <span class="sy1">=</span> <span class="coMULTI">/*maybe-const*/</span><span class="sy1">&lt;</span>Const, chunk_view<span class="sy1">&gt;</span><span class="sy4">;</span>                  <span class="co1">// exposition only</span>
    <span class="kw1">using</span> Base <span class="sy1">=</span> <span class="coMULTI">/*maybe-const*/</span><span class="sy1">&lt;</span>Const, V<span class="sy1">&gt;</span><span class="sy4">;</span>                             <span class="co1">// exposition only</span>
 
    iterator_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span> current_ <span class="sy1">=</span> iterator_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span><span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>                     <span class="co1">// exposition only</span>
    sentinel_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span> end_ <span class="sy1">=</span> sentinel_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span><span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>                         <span class="co1">// exposition only</span>
    range_difference_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span> n_ <span class="sy1">=</span> <span class="nu0">0</span><span class="sy4">;</span>                                    <span class="co1">// exposition only</span>
    range_difference_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span> missing_ <span class="sy1">=</span> <span class="nu0">0</span><span class="sy4">;</span>                              <span class="co1">// exposition only</span>
 
    <span class="kw4">constexpr</span> iterator<span class="br0">(</span>Parent<span class="sy2">*</span> parent, iterator_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span> current,        <span class="co1">// exposition only</span>
                       range_difference_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span> missing <span class="sy1">=</span> <span class="nu0">0</span><span class="br0">)</span><span class="sy4">;</span>
 
  <span class="kw1">public</span><span class="sy4">:</span>
    <span class="kw1">using</span> iterator_category <span class="sy1">=</span> input_iterator_tag<span class="sy4">;</span>
    <span class="kw1">using</span> iterator_concept <span class="sy1">=</span> <span class="coMULTI">/* see description */</span><span class="sy4">;</span>
    <span class="kw1">using</span> value_type <span class="sy1">=</span> decltype<span class="br0">(</span><a href="../ranges/take_view.html"><span class="kw2927">views::<span class="me2">take</span></span></a><span class="br0">(</span>subrange<span class="br0">(</span>current_, end_<span class="br0">)</span>, n_<span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
    <span class="kw1">using</span> difference_type <span class="sy1">=</span> range_difference_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span><span class="sy4">;</span>
 
    iterator<span class="br0">(</span><span class="br0">)</span> <span class="sy1">=</span> <span class="kw1">default</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> iterator<span class="br0">(</span>iterator<span class="sy1">&lt;</span><span class="sy3">!</span>Const<span class="sy1">&gt;</span> i<span class="br0">)</span>
      requires Const <span class="sy3">&amp;&amp;</span> convertible_to<span class="sy1">&lt;</span>iterator_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span>, iterator_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;&gt;</span>
                     <span class="sy3">&amp;&amp;</span> convertible_to<span class="sy1">&lt;</span>sentinel_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span>, sentinel_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;&gt;</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> iterator_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span> base<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> value_type operator<span class="sy2">*</span><span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> iterator<span class="sy3">&amp;</span> operator<span class="sy2">++</span><span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> iterator operator<span class="sy2">++</span><span class="br0">(</span><span class="kw4">int</span><span class="br0">)</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> iterator<span class="sy3">&amp;</span> operator<span class="sy2">--</span><span class="br0">(</span><span class="br0">)</span> requires bidirectional_range<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> iterator operator<span class="sy2">--</span><span class="br0">(</span><span class="kw4">int</span><span class="br0">)</span> requires bidirectional_range<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> iterator<span class="sy3">&amp;</span> operator<span class="sy2">+</span><span class="sy1">=</span><span class="br0">(</span>difference_type x<span class="br0">)</span>
      requires random_access_range<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> iterator<span class="sy3">&amp;</span> operator<span class="sy2">-</span><span class="sy1">=</span><span class="br0">(</span>difference_type x<span class="br0">)</span>
      requires random_access_range<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> value_type operator<span class="br0">[</span><span class="br0">]</span><span class="br0">(</span>difference_type n<span class="br0">)</span> <span class="kw4">const</span>
      requires random_access_range<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span><span class="sy4">;</span>
 
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> operator<span class="sy1">==</span><span class="br0">(</span><span class="kw4">const</span> iterator<span class="sy3">&amp;</span> x, <span class="kw4">const</span> iterator<span class="sy3">&amp;</span> y<span class="br0">)</span><span class="sy4">;</span>
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> operator<span class="sy1">==</span><span class="br0">(</span><span class="kw4">const</span> iterator<span class="sy3">&amp;</span> x, default_sentinel_t<span class="br0">)</span><span class="sy4">;</span>
 
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> operator<span class="sy1">&lt;</span><span class="br0">(</span><span class="kw4">const</span> iterator<span class="sy3">&amp;</span> x, <span class="kw4">const</span> iterator<span class="sy3">&amp;</span> y<span class="br0">)</span>
      requires random_access_range<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span><span class="sy4">;</span>
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> operator<span class="sy1">&gt;</span><span class="br0">(</span><span class="kw4">const</span> iterator<span class="sy3">&amp;</span> x, <span class="kw4">const</span> iterator<span class="sy3">&amp;</span> y<span class="br0">)</span>
      requires random_access_range<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span><span class="sy4">;</span>
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> operator<span class="sy1">&lt;=</span><span class="br0">(</span><span class="kw4">const</span> iterator<span class="sy3">&amp;</span> x, <span class="kw4">const</span> iterator<span class="sy3">&amp;</span> y<span class="br0">)</span>
      requires random_access_range<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span><span class="sy4">;</span>
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> operator<span class="sy1">&gt;=</span><span class="br0">(</span><span class="kw4">const</span> iterator<span class="sy3">&amp;</span> x, <span class="kw4">const</span> iterator<span class="sy3">&amp;</span> y<span class="br0">)</span>
      requires random_access_range<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span><span class="sy4">;</span>
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> <span class="kw4">auto</span> operator<span class="sy1">&lt;=&gt;</span><span class="br0">(</span><span class="kw4">const</span> iterator<span class="sy3">&amp;</span> x, <span class="kw4">const</span> iterator<span class="sy3">&amp;</span> y<span class="br0">)</span>
      requires random_access_range<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
               three_way_comparable<span class="sy1">&lt;</span>iterator_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;&gt;</span><span class="sy4">;</span>
 
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> iterator operator<span class="sy2">+</span><span class="br0">(</span><span class="kw4">const</span> iterator<span class="sy3">&amp;</span> i, difference_type n<span class="br0">)</span>
      requires random_access_range<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span><span class="sy4">;</span>
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> iterator operator<span class="sy2">+</span><span class="br0">(</span>difference_type n, <span class="kw4">const</span> iterator<span class="sy3">&amp;</span> i<span class="br0">)</span>
      requires random_access_range<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span><span class="sy4">;</span>
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> iterator operator<span class="sy2">-</span><span class="br0">(</span><span class="kw4">const</span> iterator<span class="sy3">&amp;</span> i, difference_type n<span class="br0">)</span>
      requires random_access_range<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span><span class="sy4">;</span>
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> difference_type operator<span class="sy2">-</span><span class="br0">(</span><span class="kw4">const</span> iterator<span class="sy3">&amp;</span> x, <span class="kw4">const</span> iterator<span class="sy3">&amp;</span> y<span class="br0">)</span>
      requires sized_sentinel_for<span class="sy1">&lt;</span>iterator_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span>, iterator_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;&gt;</span><span class="sy4">;</span>
 
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> difference_type operator<span class="sy2">-</span><span class="br0">(</span>default_sentinel_t y, <span class="kw4">const</span> iterator<span class="sy3">&amp;</span> x<span class="br0">)</span>
      requires sized_sentinel_for<span class="sy1">&lt;</span>sentinel_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span>, iterator_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;&gt;</span><span class="sy4">;</span>
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> difference_type operator<span class="sy2">-</span><span class="br0">(</span><span class="kw4">const</span> iterator<span class="sy3">&amp;</span> x, default_sentinel_t y<span class="br0">)</span>
      requires sized_sentinel_for<span class="sy1">&lt;</span>sentinel_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span>, iterator_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;&gt;</span><span class="sy4">;</span>
  <span class="br0">}</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<h4><span class="mw-headline" id="Class_template_std::ranges::slide_view">Class template <span class="t-lc">std::ranges::slide_view</span></span></h4>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">namespace</span> std<span class="sy4">::</span><span class="me2">ranges</span> <span class="br0">{</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> V<span class="sy1">&gt;</span>
  concept <span class="coMULTI">/*slide-caches-nothing*/</span> <span class="sy1">=</span> random_access_range<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> <span class="co1">// exposition only</span>
                                  <span class="sy3">&amp;&amp;</span> sized_range<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span><span class="sy4">;</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> V<span class="sy1">&gt;</span>
  concept <span class="coMULTI">/*slide-caches-last*/</span> <span class="sy1">=</span>                           <span class="co1">// exposition only</span>
    <span class="sy3">!</span><span class="coMULTI">/*slide-caches-nothing*/</span><span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> bidirectional_range<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> common_range<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span><span class="sy4">;</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> V<span class="sy1">&gt;</span>
  concept <span class="coMULTI">/*slide-caches-first*/</span> <span class="sy1">=</span>                          <span class="co1">// exposition only</span>
    <span class="sy3">!</span><span class="coMULTI">/*slide-caches-nothing*/</span><span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> <span class="sy3">!</span><span class="coMULTI">/*slide-caches-last*/</span><span class="sy1">&lt;</span>V<span class="sy1">&gt;</span><span class="sy4">;</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span>forward_range V<span class="sy1">&gt;</span>
    requires view<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span>
  <span class="kw1">class</span> slide_view <span class="sy4">:</span> <span class="kw1">public</span> view_interface<span class="sy1">&lt;</span>slide_view<span class="sy1">&lt;</span>V<span class="sy1">&gt;&gt;</span> <span class="br0">{</span>
    V base_ <span class="sy1">=</span> V<span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>                      <span class="co1">// exposition only</span>
    range_difference_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> n_ <span class="sy1">=</span> <span class="nu0">0</span><span class="sy4">;</span>       <span class="co1">// exposition only</span>
 
    <span class="co1">// class template slide_view::iterator</span>
    <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw4">bool</span><span class="sy1">&gt;</span> <span class="kw1">class</span> iterator<span class="sy4">;</span>      <span class="co1">// exposition only</span>
 
    <span class="co1">// class slide_view::sentinel</span>
    <span class="kw1">class</span> sentinel<span class="sy4">;</span>                     <span class="co1">// exposition only</span>
 
  <span class="kw1">public</span><span class="sy4">:</span>
    slide_view<span class="br0">(</span><span class="br0">)</span> requires default_initializable<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> <span class="sy1">=</span> <span class="kw1">default</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> <span class="kw1">explicit</span> slide_view<span class="br0">(</span>V base, range_difference_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> n<span class="br0">)</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> <span class="kw4">auto</span> begin<span class="br0">(</span><span class="br0">)</span>
      requires <span class="br0">(</span><span class="sy3">!</span><span class="br0">(</span><span class="coMULTI">/*simple-view*/</span><span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> <span class="coMULTI">/*slide-caches-nothing*/</span><span class="sy1">&lt;</span><span class="kw4">const</span> V<span class="sy1">&gt;</span><span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> <span class="kw4">auto</span> begin<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span> requires <span class="coMULTI">/*slide-caches-nothing*/</span><span class="sy1">&lt;</span><span class="kw4">const</span> V<span class="sy1">&gt;</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> <span class="kw4">auto</span> end<span class="br0">(</span><span class="br0">)</span>
      requires <span class="br0">(</span><span class="sy3">!</span><span class="br0">(</span><span class="coMULTI">/*simple-view*/</span><span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> <span class="coMULTI">/*slide-caches-nothing*/</span><span class="sy1">&lt;</span><span class="kw4">const</span> V<span class="sy1">&gt;</span><span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> <span class="kw4">auto</span> end<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span> requires <span class="coMULTI">/*slide-caches-nothing*/</span><span class="sy1">&lt;</span><span class="kw4">const</span> V<span class="sy1">&gt;</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> <span class="kw4">auto</span> size<span class="br0">(</span><span class="br0">)</span> requires sized_range<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> <span class="kw4">auto</span> size<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span> requires sized_range<span class="sy1">&lt;</span><span class="kw4">const</span> V<span class="sy1">&gt;</span><span class="sy4">;</span>
  <span class="br0">}</span><span class="sy4">;</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> R<span class="sy1">&gt;</span>
    slide_view<span class="br0">(</span>R<span class="sy3">&amp;&amp;</span> r, range_difference_t<span class="sy1">&lt;</span>R<span class="sy1">&gt;</span><span class="br0">)</span> <span class="sy2">-</span><span class="sy1">&gt;</span> slide_view<span class="sy1">&lt;</span><a href="../ranges/all_view.html"><span class="kw2919">views::<span class="me2">all_t</span></span></a><span class="sy1">&lt;</span>R<span class="sy1">&gt;&gt;</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<h4><span class="mw-headline" id="Class_template_std::ranges::slide_view::iterator">Class template <span class="t-lc">std::ranges::slide_view::iterator</span></span></h4>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">namespace</span> std<span class="sy4">::</span><span class="me2">ranges</span> <span class="br0">{</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span>forward_range V<span class="sy1">&gt;</span>
    requires view<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw4">bool</span> Const<span class="sy1">&gt;</span>
  <span class="kw1">class</span> slide_view<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">iterator</span> <span class="br0">{</span>
    <span class="kw1">using</span> Base <span class="sy1">=</span> <span class="coMULTI">/*maybe-const*/</span><span class="sy1">&lt;</span>Const, V<span class="sy1">&gt;</span><span class="sy4">;</span>             <span class="co1">// exposition only</span>
    iterator_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span> current_   <span class="sy1">=</span> iterator_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span><span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>   <span class="co1">// exposition only</span>
    iterator_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span> last_ele_  <span class="sy1">=</span> iterator_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span><span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>   <span class="co1">// exposition only,</span>
                          <span class="co1">// present only if Base models slide-caches-first</span>
    range_difference_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span> n_ <span class="sy1">=</span> <span class="nu0">0</span><span class="sy4">;</span>                    <span class="co1">// exposition only</span>
 
    <span class="kw4">constexpr</span> iterator<span class="br0">(</span>iterator_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span> current, range_difference_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span> n<span class="br0">)</span> <span class="co1">// exposition only</span>
      requires <span class="br0">(</span><span class="sy3">!</span><span class="coMULTI">/*slide-caches-first*/</span><span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span><span class="br0">)</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> iterator<span class="br0">(</span>iterator_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span> current, iterator_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span> last_ele,  <span class="co1">// exposition only</span>
                       range_difference_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span> n<span class="br0">)</span>
      requires <span class="coMULTI">/*slide-caches-first*/</span><span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span><span class="sy4">;</span>
 
  <span class="kw1">public</span><span class="sy4">:</span>
    <span class="kw1">using</span> iterator_category <span class="sy1">=</span> input_iterator_tag<span class="sy4">;</span>
    <span class="kw1">using</span> iterator_concept <span class="sy1">=</span> <span class="coMULTI">/* see description */</span><span class="sy4">;</span>
    <span class="kw1">using</span> value_type <span class="sy1">=</span> decltype<span class="br0">(</span><a href="http://en.cppreference.com/w/cpp/ranges/counted_view"><span class="kw2918">views::<span class="me2">counted</span></span></a><span class="br0">(</span>current_, n_<span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
    <span class="kw1">using</span> difference_type <span class="sy1">=</span> range_difference_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span><span class="sy4">;</span>
 
    iterator<span class="br0">(</span><span class="br0">)</span> <span class="sy1">=</span> <span class="kw1">default</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> iterator<span class="br0">(</span>iterator<span class="sy1">&lt;</span><span class="sy3">!</span>Const<span class="sy1">&gt;</span> i<span class="br0">)</span>
      requires Const <span class="sy3">&amp;&amp;</span> convertible_to<span class="sy1">&lt;</span>iterator_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span>, iterator_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;&gt;</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> <span class="kw4">auto</span> operator<span class="sy2">*</span><span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> iterator<span class="sy3">&amp;</span> operator<span class="sy2">++</span><span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> iterator operator<span class="sy2">++</span><span class="br0">(</span><span class="kw4">int</span><span class="br0">)</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> iterator<span class="sy3">&amp;</span> operator<span class="sy2">--</span><span class="br0">(</span><span class="br0">)</span> requires bidirectional_range<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> iterator operator<span class="sy2">--</span><span class="br0">(</span><span class="kw4">int</span><span class="br0">)</span> requires bidirectional_range<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> iterator<span class="sy3">&amp;</span> operator<span class="sy2">+</span><span class="sy1">=</span><span class="br0">(</span>difference_type x<span class="br0">)</span>
      requires random_access_range<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> iterator<span class="sy3">&amp;</span> operator<span class="sy2">-</span><span class="sy1">=</span><span class="br0">(</span>difference_type x<span class="br0">)</span>
      requires random_access_range<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> <span class="kw4">auto</span> operator<span class="br0">[</span><span class="br0">]</span><span class="br0">(</span>difference_type n<span class="br0">)</span> <span class="kw4">const</span>
      requires rrandom_access_range<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span><span class="sy4">;</span>
 
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> operator<span class="sy1">==</span><span class="br0">(</span><span class="kw4">const</span> iterator<span class="sy3">&amp;</span> x, <span class="kw4">const</span> iterator<span class="sy3">&amp;</span> y<span class="br0">)</span><span class="sy4">;</span>
 
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> operator<span class="sy1">&lt;</span><span class="br0">(</span><span class="kw4">const</span> iterator<span class="sy3">&amp;</span> x, <span class="kw4">const</span> iterator<span class="sy3">&amp;</span> y<span class="br0">)</span>
      requires random_access_range<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span><span class="sy4">;</span>
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> operator<span class="sy1">&gt;</span><span class="br0">(</span><span class="kw4">const</span> iterator<span class="sy3">&amp;</span> x, <span class="kw4">const</span> iterator<span class="sy3">&amp;</span> y<span class="br0">)</span>
      requires random_access_range<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span><span class="sy4">;</span>
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> operator<span class="sy1">&lt;=</span><span class="br0">(</span><span class="kw4">const</span> iterator<span class="sy3">&amp;</span> x, <span class="kw4">const</span> iterator<span class="sy3">&amp;</span> y<span class="br0">)</span>
      requires random_access_range<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span><span class="sy4">;</span>
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> operator<span class="sy1">&gt;=</span><span class="br0">(</span><span class="kw4">const</span> iterator<span class="sy3">&amp;</span> x, <span class="kw4">const</span> iterator<span class="sy3">&amp;</span> y<span class="br0">)</span>
      requires random_access_range<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span><span class="sy4">;</span>
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> <span class="kw4">auto</span> operator<span class="sy1">&lt;=&gt;</span><span class="br0">(</span><span class="kw4">const</span> iterator<span class="sy3">&amp;</span> x, <span class="kw4">const</span> iterator<span class="sy3">&amp;</span> y<span class="br0">)</span>
      requires random_access_range<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
               three_way_comparable<span class="sy1">&lt;</span>iterator_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;&gt;</span><span class="sy4">;</span>
 
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> iterator operator<span class="sy2">+</span><span class="br0">(</span><span class="kw4">const</span> iterator<span class="sy3">&amp;</span> i, difference_type n<span class="br0">)</span>
      requires random_access_range<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span><span class="sy4">;</span>
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> iterator operator<span class="sy2">+</span><span class="br0">(</span>difference_type n, <span class="kw4">const</span> iterator<span class="sy3">&amp;</span> i<span class="br0">)</span>
      requires random_access_range<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span><span class="sy4">;</span>
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> iterator operator<span class="sy2">-</span><span class="br0">(</span><span class="kw4">const</span> iterator<span class="sy3">&amp;</span> i, difference_type n<span class="br0">)</span>
      requires random_access_range<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span><span class="sy4">;</span>
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> difference_type operator<span class="sy2">-</span><span class="br0">(</span><span class="kw4">const</span> iterator<span class="sy3">&amp;</span> x, <span class="kw4">const</span> iterator<span class="sy3">&amp;</span> y<span class="br0">)</span>
      requires sized_sentinel_for<span class="sy1">&lt;</span>iterator_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;</span>, iterator_t<span class="sy1">&lt;</span>Base<span class="sy1">&gt;&gt;</span><span class="sy4">;</span>
  <span class="br0">}</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<h4><span class="mw-headline" id="Class_std::ranges::slide_view::sentinel">Class <span class="t-lc">std::ranges::slide_view::sentinel</span></span></h4>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">namespace</span> std<span class="sy4">::</span><span class="me2">ranges</span> <span class="br0">{</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span>forward_range V<span class="sy1">&gt;</span>
    requires view<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span>
  <span class="kw1">class</span> slide_view<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">sentinel</span> <span class="br0">{</span>
    sentinel_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> end_ <span class="sy1">=</span> sentinel_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span><span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>             <span class="co1">// exposition only</span>
    <span class="kw4">constexpr</span> <span class="kw1">explicit</span> sentinel<span class="br0">(</span>sentinel_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> end<span class="br0">)</span><span class="sy4">;</span>   <span class="co1">// exposition only</span>
 
  <span class="kw1">public</span><span class="sy4">:</span>
    sentinel<span class="br0">(</span><span class="br0">)</span> <span class="sy1">=</span> <span class="kw1">default</span><span class="sy4">;</span>
 
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> operator<span class="sy1">==</span><span class="br0">(</span><span class="kw4">const</span> iterator<span class="sy1">&lt;</span><span class="kw2">false</span><span class="sy1">&gt;</span><span class="sy3">&amp;</span> x, <span class="kw4">const</span> sentinel<span class="sy3">&amp;</span> y<span class="br0">)</span><span class="sy4">;</span>
 
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> range_difference_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span>
      operator<span class="sy2">-</span><span class="br0">(</span><span class="kw4">const</span> iterator<span class="sy1">&lt;</span><span class="kw2">false</span><span class="sy1">&gt;</span><span class="sy3">&amp;</span> x, <span class="kw4">const</span> sentinel<span class="sy3">&amp;</span> y<span class="br0">)</span>
        requires sized_sentinel_for<span class="sy1">&lt;</span>sentinel_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span>, iterator_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;&gt;</span><span class="sy4">;</span>
 
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> range_difference_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span>
      operator<span class="sy2">-</span><span class="br0">(</span><span class="kw4">const</span> sentinel<span class="sy3">&amp;</span> y, <span class="kw4">const</span> iterator<span class="sy1">&lt;</span><span class="kw2">false</span><span class="sy1">&gt;</span><span class="sy3">&amp;</span> x<span class="br0">)</span>
        requires sized_sentinel_for<span class="sy1">&lt;</span>sentinel_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span>, iterator_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;&gt;</span><span class="sy4">;</span>
  <span class="br0">}</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<h4><span class="mw-headline" id="Class_template_std::ranges::chunk_by_view">Class template <span class="t-lc">std::ranges::chunk_by_view</span></span></h4>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">namespace</span> std<span class="sy4">::</span><span class="me2">ranges</span> <span class="br0">{</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span>forward_range V, indirect_binary_predicate<span class="sy1">&lt;</span>iterator_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span>, iterator_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;&gt;</span> Pred<span class="sy1">&gt;</span>
    requires view<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> is_object_v<span class="sy1">&lt;</span>Pred<span class="sy1">&gt;</span>
  <span class="kw1">class</span> chunk_by_view <span class="sy4">:</span> <span class="kw1">public</span> view_interface<span class="sy1">&lt;</span>chunk_by_view<span class="sy1">&lt;</span>V, Pred<span class="sy1">&gt;&gt;</span> <span class="br0">{</span>
    V base_ <span class="sy1">=</span> V<span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>                          <span class="co1">// exposition only</span>
    <span class="coMULTI">/*copyable-box*/</span><span class="sy1">&lt;</span>Pred<span class="sy1">&gt;</span> pred_ <span class="sy1">=</span> Pred<span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>  <span class="co1">// exposition only</span>
 
    <span class="co1">// class chunk_by_view::iterator</span>
    <span class="kw1">class</span> iterator<span class="sy4">;</span>                         <span class="co1">// exposition only</span>
 
  <span class="kw1">public</span><span class="sy4">:</span>
    chunk_by_view<span class="br0">(</span><span class="br0">)</span>
        requires default_initializable<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> default_initializable<span class="sy1">&lt;</span>Pred<span class="sy1">&gt;</span> <span class="sy1">=</span> <span class="kw1">default</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> <span class="kw1">explicit</span> chunk_by_view<span class="br0">(</span>V base, Pred pred<span class="br0">)</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> V base<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span> <span class="sy3">&amp;</span> requires copy_constructible<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> <span class="br0">{</span> <span class="kw1">return</span> base_<span class="sy4">;</span> <span class="br0">}</span>
    <span class="kw4">constexpr</span> V base<span class="br0">(</span><span class="br0">)</span> <span class="sy3">&amp;&amp;</span> <span class="br0">{</span> <span class="kw1">return</span> std<span class="sy4">::</span><span class="me2">move</span><span class="br0">(</span>base_<span class="br0">)</span><span class="sy4">;</span> <span class="br0">}</span>
 
    <span class="kw4">constexpr</span> <span class="kw4">const</span> Pred<span class="sy3">&amp;</span> pred<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> iterator begin<span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> <span class="kw4">auto</span> end<span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> iterator_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> <span class="coMULTI">/*find-next*/</span><span class="br0">(</span>iterator_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span><span class="br0">)</span><span class="sy4">;</span>   <span class="co1">// exposition only</span>
    <span class="kw4">constexpr</span> iterator_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> <span class="coMULTI">/*find-prev*/</span><span class="br0">(</span>iterator_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span><span class="br0">)</span>    <span class="co1">// exposition only</span>
      requires bidirectional_range<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span><span class="sy4">;</span>
  <span class="br0">}</span><span class="sy4">;</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> R, <span class="kw1">class</span> Pred<span class="sy1">&gt;</span>
    chunk_by_view<span class="br0">(</span>R<span class="sy3">&amp;&amp;</span>, Pred<span class="br0">)</span> <span class="sy2">-</span><span class="sy1">&gt;</span> chunk_by_view<span class="sy1">&lt;</span><a href="../ranges/all_view.html"><span class="kw2919">views::<span class="me2">all_t</span></span></a><span class="sy1">&lt;</span>R<span class="sy1">&gt;</span>, Pred<span class="sy1">&gt;</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<h4><span class="mw-headline" id="Class_template_std::ranges::chunk_by_view::iterator">Class template <span class="t-lc">std::ranges::chunk_by_view::iterator</span></span></h4>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">namespace</span> std<span class="sy4">::</span><span class="me2">ranges</span> <span class="br0">{</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span>forward_range V, indirect_binary_predicate<span class="sy1">&lt;</span>iterator_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span>, iterator_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;&gt;</span> Pred<span class="sy1">&gt;</span>
    requires view<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> is_object_v<span class="sy1">&lt;</span>Pred<span class="sy1">&gt;</span>
  <span class="kw1">class</span> chunk_by_view<span class="sy1">&lt;</span>V, Pred<span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">iterator</span> <span class="br0">{</span>
    chunk_by_view<span class="sy2">*</span> parent_ <span class="sy1">=</span> nullptr<span class="sy4">;</span>           <span class="co1">// exposition only</span>
    iterator_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> current_ <span class="sy1">=</span> iterator_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span><span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>   <span class="co1">// exposition only</span>
    iterator_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> next_    <span class="sy1">=</span> iterator_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span><span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>   <span class="co1">// exposition only</span>
 
    <span class="kw4">constexpr</span> iterator<span class="br0">(</span>chunk_by_view<span class="sy3">&amp;</span> parent, iterator_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> current,    <span class="co1">// exposition only</span>
                       iterator_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> next<span class="br0">)</span><span class="sy4">;</span>
 
  <span class="kw1">public</span><span class="sy4">:</span>
    <span class="kw1">using</span> value_type <span class="sy1">=</span> subrange<span class="sy1">&lt;</span>iterator_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;&gt;</span><span class="sy4">;</span>
    <span class="kw1">using</span> difference_type  <span class="sy1">=</span> range_difference_t<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span><span class="sy4">;</span>
    <span class="kw1">using</span> iterator_category <span class="sy1">=</span> input_iterator_tag<span class="sy4">;</span>
    <span class="kw1">using</span> iterator_concept <span class="sy1">=</span> <span class="coMULTI">/* see description */</span><span class="sy4">;</span>
 
    iterator<span class="br0">(</span><span class="br0">)</span> <span class="sy1">=</span> <span class="kw1">default</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> value_type operator<span class="sy2">*</span><span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> iterator<span class="sy3">&amp;</span> operator<span class="sy2">++</span><span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> iterator operator<span class="sy2">++</span><span class="br0">(</span><span class="kw4">int</span><span class="br0">)</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> iterator<span class="sy3">&amp;</span> operator<span class="sy2">--</span><span class="br0">(</span><span class="br0">)</span> requires bidirectional_range<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> iterator operator<span class="sy2">--</span><span class="br0">(</span><span class="kw4">int</span><span class="br0">)</span> requires bidirectional_range<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span><span class="sy4">;</span>
 
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> operator<span class="sy1">==</span><span class="br0">(</span><span class="kw4">const</span> iterator<span class="sy3">&amp;</span> x, <span class="kw4">const</span> iterator<span class="sy3">&amp;</span> y<span class="br0">)</span><span class="sy4">;</span>
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> operator<span class="sy1">==</span><span class="br0">(</span><span class="kw4">const</span> iterator<span class="sy3">&amp;</span> x, default_sentinel_t<span class="br0">)</span><span class="sy4">;</span>
  <span class="br0">}</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>

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